My previously stable Windows PC now freezes and shuts off shortly after starting games, sometimes with a buzzing sound in the headset. After restarting, game performance can be much worse than usual. Graphics drivers are updated, malware scans have found nothing, and there is plenty of free storage.
What should I check before paying for repairs or replacing parts?
Start with CPU and GPU temperatures and utilization. Use a monitoring tool while starting a game and watch what happens just before the freeze. If temperatures climb rapidly or clock speeds drop, that gives you a useful lead.
Check that the fans are spinning and the vents and cooler aren't packed with dust. Shut the PC down and disconnect power before cleaning inside. Don't assume the graphics card needs new thermal pads just because it's older. Get temperature readings first.
Try isolating the graphics card if your CPU has integrated graphics. Connect the monitor to the motherboard output and see whether the system stays stable during ordinary desktop use. Some CPUs don't have integrated graphics, so check the exact model first.
Don't expect good gaming performance from that test. It can narrow things down, but a stable desktop alone doesn't prove the graphics card is faulty.
A component stress test can help narrow this down too. Test the CPU and GPU separately while watching temperatures, rather than jumping straight into a combined power test. If a test causes a freeze or temperatures get excessively high, stop it and note which test was running.
A failure under load is a clue, not a diagnosis by itself. The power supply, cooling, motherboard, and other components can all affect stability.
If Windows is also slow outside games, especially when opening files or shutting down, check the drive's health as well. A storage problem is another possibility and freeing up space won't necessarily fix it.
Back up anything you want to keep before doing more troubleshooting. A Windows reinstall is an option if the checks point toward software, but I'd leave it until after the basic hardware checks rather than making it the first step.
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reg4!idx:
It would also help to post the exact CPU model, not just Core i7, along with the temperature readings.