exe programs will not work

All my exe files have been changed in windows explorer to EXE Files instead of applications. Whenever I click on anything, the message says that no program is associated with it and wants to go to the web or select from a list. I am sure there is one file missing that opens all exe files but I don't know what it is. Dell 8400 / XP Home / 3.2 P-4 processor / 4 gig ram / Trend Internet Security / Ad-Aware / Windows Defender. The only programs that will run is Internet and e-mail from the start menu. I can get to windows explorer by right clicking on start and using open. Exe will not run from the run menu either. I am using my backup drive which I keep loaded with a fresh XP but not all my programs. When booting with the backup drive, all the exe files from the infected drive work fine and are shown as applications. I need to be able to restorre that registry from this drive or find a way to do it on the infected drive win no exe working.

 

Try the association fix, sometimes it works sometimes it doesn't, but won't do any harm.

From Kelly's korner http://www.kellys-korner-xp.com/xp_abc.htm (scroll to EXE):

 

I had tried to restore from my windows cd and it will get half way through, tell me it can't open a file (an exe I suspect) then it goes black screen and quits. I can still access the drive through my backup. Is there any way to fix the actual file from another drive? I don't know the actual name of the registry in XP but I thought there might be a way. When any of the programs are run, they want to repair the current drive that I am using and not the bad one.

HELP!!!!!