are you able to boot into safe mode?  if so, try a system restore from there.

I can boot into safe mode but again can't use System Restore or launch any programs, I managed to intall Malwarebytes anti malware and Spybot but both found no malware.

well, it would appear your registry is corrupted, not sure what happened to cause it... there are possible ways to fix it, but do not know what you are willing to do or not do, and your time, effort, whether you have a backup or image, etc etc.  Maybe others can chime in if they have any easy fix other than editing the registry.   

Ummm.....What version of Windows??

If this is XP with SP3, did you follow these instructions to run System Restore from Safe Mode?

Ron

If Windows XP, was the reg file you downloaded from

http://www.kellys-korner-xp.com/xp_tweaks.htm

No 12 left column? If not try that one. Once downloaded to your hard drive double click on it to merge its contents to the registry.

I tried this but it had no effect I also downloaded his system restore fix at number 289 but this didn't work either.

I tried to restore by this method however when I boot into safe mode the mouse and the keyboard won't work, I tried to do it ordinary safe mode and it said system restore is not able to protect this machine so I'm even more confused.

Sounds like you need to do a Repair/Reinstall of Windows. Personal files won't be damaged.

Boot from your Dell WIndows Reinstallation CD.

Press R at first screen to open Recovery Console.

At C: prompt, type in: chkdsk c: /r

Press Enter and take a nice long nap while chkdsk checks the hard drive for errors. When it's done, remove the CD and see if it boots and works properly now from the hard drive.

If not, reboot from the Windows CD. Press Enter (not R) at first screen. Accept the user license, choose your version of Windows (should only be one) and finally press R on next screen to launch the Repair.

When it's done, remove the Windows CD and reboot from the hard drive. Go directly to the Microsoft update site and let it scan your system for needed updates. There probably will be a bunch that have to be reinstalled.

Ron