When the internet or Wi-Fi signal disappears on other devices just as your desktop computer is turning on, this is a classic sign of a local network conflict. Most often, the problem lies not with a physical cable break, but with the router software or the PC's network card settings, which are incorrectly processing connection requests. IP address conflict or a DHCP client table overflow are the most likely culprits for this behavior.
When you start the operating system, the network card sends out a broadcast request for an address. If the router TP-Link, Asus or MikroTik If it can't allocate a new unique identifier or mistakenly assigns an address already occupied by a smartphone or TV, the connection is lost for everyone. In some cases, the cause is a faulty network adapter, which generates electrical interference or packet storms, literally "clogging up" the airwaves.
In this article, we'll examine the mechanics of these failures in detail and offer a step-by-step diagnostic algorithm. You don't need to be a network engineer to troubleshoot the issue, but you will need to be careful when entering settings into the router's web interface. We'll cover both Windows software settings and the router's configuration.
IP address conflict: the main cause of failures
The main reason why the network crashes when starting a PC is due to duplicate IP addresses. DHCP (Dynamic Host Configuration Protocol) automatically assigns addresses to connected devices from a defined pool. If your Windows network card settings are manually configured with a static address that matches the address of another device (such as a smart bulb or phone), a critical error occurs.
⚠️ Attention: If you previously set a static IP address for gaming or port forwarding, make sure that this address is outside the router's automatic allocation range. For example, if the DHCP pool is 192.168.1.100 to 192.168.1.200, the static address should be outside these ranges (e.g., 192.168.1.50).
The system detects a duplicate and attempts to reassign addresses, which causes a brief connection interruption for all clients. In the worst case, the router freezes and requires a reboot. To check the current status, you can use the command line. Enter the command ipconfig /all and look at the line "IPv4 Address".
The solution is to set the network card to obtain an address automatically. To do this, open Control Panel → Network and Internet → Network and Sharing Center, select your connection and properties Internet Protocol version 4 (TCP/IPv4)Make sure the automatic receipt boxes are checked.
Router DHCP client pool is full
Many home routers have a limited capacity for simultaneously serving clients. By default, the address pool may be configured for 50 or 100 devices, but in reality, budget models Zyxel or Tenda They can become unstable with only 15-20 active connections. When you turn on your computer, it requests a new address, and if the limit is reached, the router may reset the oldest connection or simply stop responding.
This is especially relevant for smart homes, where numerous IoT devices (sockets, sensors, cameras) are constantly connected. The computer in this chain acts as a trigger, requiring new resource allocation, which becomes the final straw for the router.
You should go to the LAN settings in the DHCP Server section and check the pool size. If you have many devices connected, it might be worth expanding the range. It's also helpful to check the Client List and delete unknown or old devices that are no longer in use but are listed in the database.
| Parameter | Recommended value | Description |
|---|---|---|
| Start IP Address | 192.168.1.2 | Pool starting address |
| End IP Address | 192.168.1.254 | Maximum pool address |
| Lease Time | 120 minutes | Address rental time |
| Max Clients | 32 (for budget) | Connection limit |
Problems with drivers and PC network card
Incorrect network card drivers are a common cause of packet storms during system startup. Outdated or corrupted drivers can send erroneous broadcast requests, which paralyze the wireless network. This is especially common with integrated Realtek cards or older D-Link adapters.
Check the Device Manager in Windows. If a yellow exclamation mark appears next to the network adapter, the device is not working properly. Even if there is no exclamation mark, we recommend completely uninstalling the driver through the Control Panel and installing the latest version from the motherboard manufacturer's official website, rather than through Windows Update.
It's also worth paying attention to power saving settings. The system may try to conserve energy by shutting down the card at inopportune moments or, conversely, by supplying excessive current during initialization, which causes a voltage surge on the router port.
⚠️ Attention: When updating drivers, use only official sources. Driver packs and automatic installers often install generic but unstable versions of software that may conflict with your motherboard's specific chipset.
☑️ Actions with drivers
Windows energy saving settings
The Windows operating system has a feature that allows you to disable the network adapter to save power. When you turn on the computer, this mechanism may malfunction, causing a cyclical reconnection that clutters the network. To disable this feature, go to the network adapter properties.
In the properties window, click the button Tune (Configure) and go to the tab Power managementUncheck "Allow the computer to turn off this device to save power." This will prevent the system from silencing the card in the background.
Additionally, the Windows power plan may be set to a high-performance mode, which sharply increases the PCIe bus frequency at startup, which could theoretically interfere with the operation of the Wi-Fi module if it is physically located close to the video card or power supply.
Why does disabling energy saving help?
When this option is enabled, Windows may put the card into sleep mode, even for fractions of a second, during background processes. This causes the connection to be lost and the IP address to be re-acquired, which puts a strain on the router.
Diagnostics via command line
For a thorough diagnosis, you need to use Windows' built-in utilities. They allow you to see exactly what's happening on the network at the time of the failure. Open a command prompt as administrator and use the following commands to reset the TCP/IP stack.
DNS cache or ARP table errors often accumulate in the system, preventing it from correctly identifying devices on the network. Clearing these tables helps eliminate "phantom" connections.
ipconfig /flushdnsipconfig /release
ipconfig /renew
netsh int ip reset
netsh winsock reset
After running these commands, be sure to restart your computer. If the problem is caused by a software glitch in the Windows networking stack, these steps should resolve it. It's also a good idea to check the Windows event logs (eventvwr.msc) in the section "Windows Logs → System" for source errors Dhcp-Client or e1dexpress (for Intel) at power-on.
Hardware conflicts and interference
A physical factor also cannot be ruled out. If the PC's network card is faulty, it may generate electrical interference or a frame "storm" that interferes with the Wi-Fi frequency (especially if the router is located near the system unit). When the PC is turned on, there is a surge in current consumption, which can cause a voltage drop on the router port if it is connected to the same power supply or extension cord.
Check the integrity of the LAN cable. A short circuit in the twisted pair cable can cause a short circuit when power is supplied to the port (PoE or just a signal), which the router's protection mechanisms will counter by rebooting the wireless module.
Also, pay attention to the antenna placement. If the router antennas are located close to the metal case of the PC or the graphics card, electromagnetic noise levels will increase sharply when running heavy applications (such as games or rendering), overwhelming the useful signal.
⚠️ Attention: If the problem persists after all software adjustments, try replacing the LAN cable connecting the PC to the router. Cheap, unshielded cables can create strong interference, disrupting the Wi-Fi channel.
Frequently Asked Questions (FAQ)
Why does Wi-Fi only disappear on my phone when I turn on my PC?
Most likely, your computer is receiving the same IP address that your phone is currently using (an IP conflict). The router sees a duplicate and disconnects from one of the devices, often choosing the one that connected later or has a weaker signal. Check your DHCP settings.
Can a computer virus disable Wi-Fi?
Yes, some types of malware can change network settings, set static DNS, or create bandwidth overhead, causing connection interruptions. Run a full system scan with an antivirus program.
How do I find out how many devices are connected to my router?
Go to your router's web interface (usually 192.168.0.1 or 192.168.1.1), log in, and find the "Wireless Statistics" or "Client List" section. All active connections will be displayed there.
Will resetting the router to factory settings help?
A reset will return all settings to their default values. If the problem was a configuration error (for example, a limited DHCP pool), this will help. However, if the issue is hardware or PC drivers, resetting the router will not resolve the issue.