Sweet lord you have an awesome rig! Anyway.....Lavasoft Adaware, Tweaknow RegCleaner, Ashampoo WinOptimizer are all pretty decent. I'd however suggest applying ALL of these tweaks:
thank you very much. i also heard that there are some pretty good memory defrags out there.... what are some good ones which dont have to be open all the time? Thanks.
Hmm.....like Harddrive defrags? I just use the one that comes embedded in Windows XP. Defragging has never really improved performance for me though. Although those tweaks in that link I gave you really performs wonders on most systems.
Just to clarify for you. You can't defrag memory. Memory is RAM, which is not the same as your hard drive. If you want to clean out your memory, restart you computer. That will completely wipe it out since RAM does not store data when power is removed from it. That's why you lose whatever you were working on if your power goes out and you didn't save.
With older file systems like FAT16 and FAT32 (used for windows 95 and 98 mostly) defragging could provide noticable performance gains and was important to do frequently. NTFS (the file system used on most WindowsXP systems) on other than doesn't get fragmented nearly as easily. Also, as hard drives become larger in capacity, the bits have to be clumped closer together. That means there is less time wasted moving from bit to bit. With drives as fast as they are now in terms of average seek time, fragmentation creates little performance drain, especially on an NTFS system. It still helps to do it though, especially if you've installed/uninstalled lots of stuff and/or you do a lot of video editing or other disk intensive tasks.
As for programs to do that, just use the windows defragmenter.
If you want a good tweak program, X-setup is good, but be careful with it, because you can screw your system royally with it. Honestly the best way to get the best performance out of a computer is to know as much about it as possible and make your own tweaks.