Windows Installer doesnt work

> Whenever I go to install something, an error comes up, it
> reads: "The Windows Service Installer could not be
> accessed. This can accur if you are running Windows in
> safe mode, or if the Windows Installer is not correctly
> installed. Contact your support personnel for
> assistance." I have no idea how to fix this problem, I
> just know it needs to be fixed so I can install software
> once again. I know tha Windows is not in safe mode, and I
> don't know how to contact my support personnel, I don't
> even know if I have them... So I figured that this is the
> next best thing. I don't know how this works, but if it's
> possible I would like an answer for my question emailed
> to me, I don't even know how I got here... Thank you.
> Jeff Snyder