Betas and CTPs of VS 2005 may not uninstall cleanly. (They were never meant for production machines, but only for testing/evaluation purposes.) So you may have some garbage from a beta or CTP confusing the VS 2005 RTM installer. I would try the following:
Uninstall VS 2005, .NET Framework 2.0, SQL 2005 Express, and related tools.
forgot something!
LeHobbit31
paisanperu
did you have any precious betas installed Do you get any error message
teuneboon
Nats_007
Vishwa Mohan Saxena