Have you considered using the Dell Reinstall system.
It is on a hidden partition and will restore the
system to the way it was the day you got it.
Just reboot and click F12 ( please read the manual first!! )
this will almost always correct this sort of behavior.
In my 20 years I have rarely been able to find a cure for
such an " Unusual " error, and I have had many. I long since
gave up trying to find the fix, it is easier to do a clean
install, which the Dell Recovery will do.
I promise it will take more time to correct the error than
to reinstall, reconfigure etc. It is well worth the effort.
Received New PC Dell on 05. April, VISTA pre installed. Diemension 9200 Intel Viiv Tech. 2 Duo E6600 2.4GHz, with 2G. Ram. NVIDIA GeForce 7900GS with 256MB.It freezes time to tiime, CD drive does not read the CD suddenly any more. To read the cd must reboot. Great headache, request help. I have burnt text files and Pictures on different CDs on this Computer to test. The problem remains. A million thanks, joel