unable to assolate driver dependencies

Recently i changed my video card from nvidia to ati.

Put simply i now have a problem with either video/audio and windows xp pro.
The problem is sometimes my monitor goes into standby.

I have reason to believe that the file 'nvidia wdm tvaudio crossbar'
The actual error is;
"The nVidia WDM TVAudio Crossbar service failed to start due to the following error:
The system cannot find the file specified."

I have tried the usual solutions like completely delete video files and re-install,
this includes going through the registry, i found and crossbar but regedit will not let me delete even in safe mode the the video drivers un-installed

I already have a solution and that is to re-install windows, however i dont want to do it.

Regards
Adam C

Uninstall any software and drivers for the ati nic that you might have installed (go to system properties, hardware, device manager and clik uninstall. Go to Add/Remove software in cp and remove all ati related stuff). Then install the old nic. Reinstall it's drivers reboot all that good stuff. THEN uninstall EVERYTHING nvidia (same as what you did for the ati in the above step) and shutdown the system. Pop the ati in and you "should" be in business.
The video card is one of those things you just can't pop out and have it stop working then install a new one and expect it to work.

Look to see if there is any Nvidia service that is running or trying to run. Disable it. There is a NVIDIA Display Driver Service, maybe on for the WDM TVAudio Crossbar that didn't go away with the driver uninstall.

If you never did a proper uninstall then do what Gollo says.

on the left, detonator destroyer or rip will tidy up that which the uninstallers leave behind.

Or you can cheat and do what noo said :D

I was almost certain there was a utility to do that but I had no clue where ;)

thanks everyone, i'll try those suggestions now.

regards
adam c