How to Find What's Using 100% CPU or Disk on Windows
Task Manager names the process, Resource Monitor names the file, and Event Viewer explains the pattern. Here is how to read all three properly.
A slow Windows PC almost always has one dominant cause: a saturated disk, too many startup programs, thermal throttling, or a background process misbehaving. These guides show you how to identify which one it is before changing anything, then fix that specific problem — rather than applying a dozen "tweaks" and hoping.
Task Manager names the process, Resource Monitor names the file, and Event Viewer explains the pattern. Here is how to read all three properly.
Separate the boot itself from the login that follows — they have different causes. Task Manager's startup impact ratings tell you which to fix.
Windows hoards update backups, hibernation files, restore points and temp data. Reclaim 20–60GB using built-in tools, without touching a personal file.
Windows 11 has its own slowdowns — VBS, widgets, the redesigned Start menu and a scheduler that mishandles some CPUs. Here is what is specific to 11.
Stop guessing. Use Task Manager to find whether your disk, RAM, CPU or temperature is the bottleneck, then apply the one fix that matches.