For the past two days, my Windows PC has gone from booting in about 15 seconds to taking 10–15 minutes just to reach the sign-in screen. The sign-in screen itself looks normal, but after logging in, all three monitors turn black while the mouse cursor remains visible and usable. Restarting Windows Explorer through Task Manager brings the desktop back, but the entire system is still extremely sluggish—clicks can take several minutes to register and browsers never finish loading pages. I've tried several diagnostic and repair steps with no improvement. What could be causing this, and what should I check first?
4 Answers
First, open Task Manager and check the Performance tab while the computer is slow. Pay special attention to Disk usage and the disk response time. If the drive is stuck near 100% usage or has very high response times, the system drive may be failing. Back up important files immediately before doing more repairs.
Booting from a Windows recovery environment or a Linux live USB can help separate a Windows problem from a hardware problem. If the live system runs reasonably well, Windows, its drivers, or an update may be damaged. If even the live environment is painfully slow, suspect the drive or another hardware issue.
Try starting Windows in Safe Mode. If it works normally there, a recent update, graphics driver, startup program, or other third-party software may be responsible. You can then uninstall a recent update or reinstall the display driver. If Safe Mode is also extremely slow, hardware—especially the system drive—is more likely.
This sounds like it could be a problem with the C: drive or its file system. Check the drive’s SMART health data with a disk-monitoring utility such as CrystalDiskInfo, or use the manufacturer’s diagnostic tool. If it reports warnings, errors, or a failing status, replace the drive rather than trying to repair Windows repeatedly.
A failing system drive can cause both the extremely long boot and the delays after signing in, so I’d prioritize checking and backing up the data before rolling back updates.