I installed every 2005 Express language, plus  SQL  and the Managment Studio and SQL Books Online, over the same machine (XP SP2) and haven't any problems using them... I followed the guidelines to intall given at the Visual Studio Site by using the automatic unistall utility for the Beta 2 I already had... So I think order of installation as depicted in those guidelines are important... Perhaps you should try uninstalling and reinstalling again in the proper order.

Tonatiúh Smiley