If the Visual Studio 2005 and below IDE is not executed from an elevated account there are a multitude of things that will fail. With your experience with the Windows shell and various COM technologies I don't really understand why you have not experienced this. Perhaps you have modified the Windows7 UAC behavior or maybe your IDE is in-fact executing elevated without your knowledge.
1.) How are you attaching your debugger to elevated or system processes?
2.) How are you installing/registering COM components and/or shell extensions?
It may be that we are developing different types of software and therefore you have never required elevation.
You are probably referring to compatibility issues. There are a multitude of new Microsoft technologies which probably caused minor incompatibilities. Anyway I think you can get SQL Server 2005 working on Windows 7 but you will need to install Microsoft SQL Server 2005 Service Pack 3[^].
It plainly lists Windows 7 in the Supported Operating Systems section.
Tanks for yours answers, I installed Visual Studio 2005 and 2008 and any problem, with Visual Studio 6 only worked on Windows XP Mode Virtual Machine.
SQL Server 2005 32 bits is posible install, if Visual Studio 2005 is too 32 bits. I can't install SQL Server 2005 64 bits maybe incompatibity with Windows 7 or the installer is damage, but it show an error about file .cab. I believe the better option is install SQL Server 2008 (32 or 64 bits).
I am having a weired problem with VS 2005 on windows 7
after the browser closes (i am writing a web project) after i run the application, the IDE is back, but it is visually corrupted !!!!
as if the windows of the IDE are not completely drawn?! i fix this by showing a nother window (from the IDE itself) then switch back to my original window, same for project explorer, i have to get focus to the tools window then hide it to show the project explorer, this is annoying.