kaled - 8:35 am on Aug 29, 2009 (gmt 0)

Having quickly googled the subject, it would seem that your system is probably in an unstable state as a result of a partially installed servicepack. Whilst you may be able to fix the singular problem you are experiencing, a full repair-install with a ServicePack 3 disk may be the best solution.

You may need to create this disk using another computer, you should also google slipstream servicepack and look for the most generic instructions that aren't tied too closely to a specific CD burning package (unless you have that package). Naturally, you should backup critical data before installation.

Kaled.