I've recently installed CCleaner. I ran it a couple of times and it seemed to work ok, not a lot of difference, but a bit faster. Yesterday I did the same thing, but as soon as I was done, my computer ran a LOT slower. I thought this was supposed to do the opposite. I even downloaded the Defraggler, thinking it might help. nothing.Did I do something wrong? I don't know what's going on, but it's driving me nuts. I'm running on Windows XP using firefox. PLEASE, SOMEONE HELP! Thanks!
Can you check the Task Manager's Processes tab, and see if there is anything running that could make the system run slower, e.g. high CPU usage or I/O activity?
There are quite a number of options you can do to resolve it but since your PC did not get slower immediately after you ran CCleaner, I assume, the problem is not there.
Try doing another registry scan with CCleaner. There is a chance that there is a failing program that is causing registry bugs in your system, making it slow.
You can also try using check disk. Go to My Computer> right click your C: drive or the primary partition> choose Properties> Tools > Error Checking option, click Check Now> uncheck the automatically fix system errors since you are currently using the primary partition> check the scan for and attempt recovery of bad sectors> close all your running programs and start the scan which should take some time, depending on the size of your hard drive.
Or if these measures fail, try doing a system restore, otherwise if this fails as well, you may have to look or scan for a virus or reformat the system on occasion.