|If you are confident that the hard disk is working properly in your machine, then it sounds like there are file associations that may need to be repaired. It is interesting that Windows Explorer (e.g. you mentioned you can open My Computer) works on your computer, but that regular programs (.exe) will not launch. |
Is it only in double-click that they don't launch? Try right-clicking the shortcut or program and clicking "Open" and see what happens.
Try going to Control Panel or any Windows Explorer folder. Open Folder Options, and find the File Types tab. Reassociate the file association for an executable file.
If that doesn't work, download and install CCleaner from http://www.ccleaner.com -- CCleaner can safely clean your Windows registry, in case anything got goofed up over time on your computer. Clean the Registry with the Registry tab, and restart your PC.
If you really want to troubleshoot to see if things even are working, go to Start, then Run. Type in 'notepad', for instance, to see if Notepad opens, or 'mspaint' to open Paint, or any executable you know about. Then, BEFORE clicking OK in the Run box, open the Task Manager with Ctrl+Shift+Esc or Ctrl+Alt+Del. (If Task Manager doesn't even work, and you know you are an administrator or computer owner, you may need to either clean or reinstall your OS. But hopefully, Task Manager will open.)
Go to the Processes tab in Task Manager, and click OK in the Run box, now that you are watching Processes. Watch carefully if notepad.exe, or whatever task you typed pops up in that list, even if it takes a few minutes to do so, if your computer is slow.