I've been having this issue recently where my computer starts lagging horribly, the cursor moves really slow, freezes at time and even refreshing takes a while. Sometimes this happens as soon as I boot while at other times it might work fine for an hour but the problem always reoccurs. CPU usage and memory in task manager is normal if I ever manage to open task manager when the issue occurs. I scanned my PC using Norton 360 and found 0 errors. So, I did a clean install of Windows 7 but that didn't fix the issue either (took me 3 tries to reinstall the windows because the it froze midway through the installation twice). Restarting doesn't help either and it takes a long while to boot.
So, I went and got my PC checked, was told it might be a hard drive issue so I replaced my hard drive with a new one. But that doesn't seem to have helped either as the issue reoccured after like 15 mins of using my new hard drive.
I'm kinda convinced its a PSU issue but would like someone to second that before I go get a new PSU. Any other suggestions will be welcome too.
I would greatly appreciate any advice whatsoever. If I've missed out any info please don't hesitate to ask!
One last thing. The lag isn't as bad with the new hard drive but its still noticeable.