I can't do a check disk, defrag, or fresh install

Hi all,
I recently had a virus called WINLOGONHOOK that scrammbled my brain. I finally go rid of it after cancelling the process tree to explorer. While I was getting rid of it and all of its components, I think I deleted some serious files that were in system 32 and in the registry editor. When I boot the system, I get the default backdrop(blue and green rolling hills), then it loads my home page and programs. When I try to do a check disk, it says that WINDOWS WAS UNABLE TO COMPLETE THE CHECK DISK, and when I try to defrag, it will say DISK DEFRAGMENTER COULD NOT START. I've tried everything in safe mode, turned off system restore, tried a manual chkdsk /f command and nothing. When I try to put in my Windows XP disk that came with my dell computer, it wont allow me to install windows and start from scratch. Can somebody please, please help me so I stop thinking about this problem? Thank's a ton!!!:confused

 

You could try "sfc /scannow" in the Run window with your system disk in. This will check your system files and try and replace any damaged files.

http://www.updatexp.com/scannow-sfc.html

You could also consider "rebuilding" Windows (I have on at least 4-5 occasions):

XP's No-Reformat, Nondestructive Total-Rebuild Option

If your Windows Disk from Dell still isn't working ring them and get another.

 

I just tried that and it flashed the dos screen and dissapeared. I tried to install windows xp since I already had the disc in my comp, and it said no valid system partitions were found, Windows was unable to continue. Any ideas????