Cannot run computer management on Mircosoft OS.

Try entering compmgmt.msc in Start / Search box and enter.  Double click on the program icon that appears and see if it opens.  I doubt this will work if clicking on the executable file didn't work, but it's worth a try.

Let's check some of your system files:

Go to Start / All Programs / Accessories / Command Prompt and right click on command prompt and click run as Administrator.

Type sfc /scannow and enter and let it run. 
It will scan and try to fix some system files.  Hopefully it will complete without any errors it couldn't repair (if such errors occur, post back here).

While you're in command prompt type chkdsk /f /r and enter and let it run.  It will look for and fix/mark bad sectors (and one of the computer management files may be in a bad sector which can be moved unless it's hopelessly corrupted).

Are you certain the problem is limited to Computer Management/  Have you tried to enter EventViewer or Services or anyghing else in Administrative Tools?  Please try.

Do you have a genuine Windows Vista Installation Disk (or can you borrow one from ANYONE).  If none of these efforts work, our next logical step would be a system repair/upgrade and we need the disk to do that.  They aren't copy-protected so you can use anyone's copy with your own product key which governs the version installed.

Let's see where this gets us.  Good luck and I hope this helps.  If it doesn't really try hard to get your hands on a disk.