Well ever since a couple days ago my PC has been running slow, like something is stressing it out. Like, when I go on AOL Instant Messenger before the program starts up its memory usage (from task manager) is 5,000 then when it connects and it fully started up its memory usage is like 29,000! And then explorer.exe's memory usage is like 55,000! Also when I move an IM window (not buddy list) it moves VERY slow and I hear my PC stressing something (I hear like little clicks and the light on the PC is flashing, also means its working). Also, every time I restart my PC or turn it off and turn it back on I get a start up error saying "Windows did not start up successfully, we are sorry for the inconvenience, please choose the last good configuration that Windows started up in" and it says something about a hardware change that may have caused the problem... But I didn't install or uninstall anything for my Hardware! I used to get this start up error only when Installed a new Video Card Driver or installed or uninstalled any anti-virus and firewall software, but now I get it ALL THE TIME! Oh and I have ran Ad-Aware, Spybot Search and Destroy full scans, ran scandisk, defragmented my C Drive, and I still get these problems. Also to let you know I have been downloading things using Bittorrent that have required me to leave my PC on over night so there's another answer but Im not to sure... Anyway, can someone PLEASE help with this or give me a possible solution for it? Thanks a bunch. Also on ZoneAlarm before it said there have been 2 intrusions since Zone Alarm has been installed now it says there have been 6 intrusions since Zone Alarm has been installed.

The memory usage you mention does not look alarming.
The key phrase here seems to be the 'little clicks'.
That could indicate a harddisk failure. The clicks are recalibrating cycles because data cannot be read from the disk - and of course, the 'puter is slowing down because it is waiting for those data, and retrying to read them.
In extension, it could also be a failure of any device connected to any of both IDE interfaces - or a wrong setup of the IDE devices in your CMOS (aka BIOS settings) - try the auto-IDE-detect function of the BIOS. Check also if all cables inside are well seated.

Hi,
Have you heard these "little clicks" from the hard drive before? Such as when you first got the computer? Or are they new sounds?
As the other volunteer said, your hard drive could be on the way out.
Some, such as a Gateway, are not silent, but "clicks" can be heard when the computer is new; but if they start getting like a "grinding" sound, the hard drive is going bad.
A hard drive can go bad after only 2 yrs, but not normally.
Best wishes,
fredg