If you want to run Visual Studio 2005 on Windows Vista you might want to take a close look at the following two lists. They list some of the issues you might run into. In other words, make sure you can live without.
Check for running with elevated administrator permissions at http://msdn2.microsoft.com/en-us/vstudio/aa964140.aspx and additionally for running with normal user permissions at http://msdn2.microsoft.com/en-us/vstudio/aa972193.aspx.
Take good care