I was on a Dell site the other day and they had info about a specific system that stated a Bios update might be needed for some black screen problems. Maybe check your OEM to see if there are any for your system, and what they might be for.
You could set msconfig.exe, in safe mode, to boot with a basic video so you could get back into Windows, hopefully.
If you are allowing the drivers to be reinstalled, does the Compaq/HP site have drivers available you could load?