This is a strange one indeed. I got a new laptop (64-bit of course) and put Windows XP Pro x64 on it, Everything is installed perfectly, including VS.NET 2003 Enterprise and VS.NET 2005 Pro.
Now I notice I have ASP.NET debugging issues in VS.NET 2003. So I figure I'll do a reinstall or repair on VS.NET 2003 to see if that takes care of it.
Go to Control Panel, Add/Remove, click on the "Change" button for VS.NET 2003 with the DVD in the drive, get an error dialog. OK, let's just run setup.exe off the DVD, right?
"Unable to install Visual Studio on a 64-bit Operating System".
DOH! It already installed, right? I'm not going mad or anything. OK, we try running the .MSI directly. It runs OK, starts gathering information, and then it QUITS!
There is very little information on this anywhere. Does anybody have any ideas on this? It's not a big deal for me, VS.NET 2003 runs fine, its just that I get "Unable to Start the Debugger" errors in ASP.NET 1.1, and I"d like to figure out why I cannot reinstall the same product I just successfully installed a week ago, on the same OS and machine, with no changes other than that I put VS.NET 2005 on there afterward. There is only one Product Feedback item on this subject, it is very recent, and no action has been taken yet. If you have this issue, go to Product feedback and VOTE on it, and maybe somebody will get off their ass over there and look at it.
Fortunately, 64-bit is coming of age and you can find drivers now for almost everything. But, apparently, we still need to come up to speed on some 32-bit application compatibility issues!