"FAT32" would have been appropriate for "ME" but NTFS is best for "XP."
You say, "I always delete all cookies and temporary files daily. I have tried disk cleanup, defrag, registry mechanic. I just don't understand." Deleting cookies daily is not worthwhile and will slow down accessing/using Internet sites. Good anti-spyware programs will pick up any "bad" cookies that should be removed. You may have caused trouble using "Registry Mechanic." Reg "cleaners" are not recommended. See below for extended info.
{redoak}
Advice and Info re Registry 'cleaners'- excerpts from TSG, 10-07
The main reason they are apt to cause problems is because the cleaners do NOT just clean up stuff left over from uninstalls. They also "guess" that other items need to be deleted, many times incorrectly. They also attempt to "fix" references to files that no longer exist.
As a result, you can end up with programs that no longer work, functions that no longer work and in some cases a PC that will no longer boot.
There is no performance gains to be had by running these things. Windows does not read the entire registry when it is looking for something. It uses the keys which allow them to go straight to the item that they are looking for.
References:
http://www.edbott.com/weblog/?p=643
http://www.computerhope.com/registry.htm
If you really want to see how active the registry is in your normal running environment, download and run Regmon.
http://technet.microsoft.com/en-ca/sysinternals/bb896652.aspx
As you will see, the registry is constantly being accessed. If, for each of these, the entire file was being searched, your PC would be amazingly slow and not responsive.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Sorry I am unable to cite and give credit to the authors.