I have a Dell T5400 Vista x64 and after installing SP1 I get a lot of blue screens related with system_service_Exception, bad_pool_caller and others.
The problem was the Dell mouse suite preinstalled with the computer. The solution is uninstall SP1, uninstall mouse suite, upgrade the video drivers
and apply SP1.
You can see the process here:
Apagando fuegos a salto de mata: Error al instalar Vista SP1 en Dell T5400