We had a computer with VS2003 installed on it and a version (1544) of VA.
Now we have installed VS2005 (with SP1) on it as well. For some reason, VS2005 didn't see that VA was installed. So we did an unistall of VA and afterwards an installation.
But now VS2005 is only showing the startup window (here I can see that VA is integrated) but after a second or 3 it just disapears. The same happens with VS2003 but the second time VA asks for the key and it works fine.
The reason VA did not see VS2005 is that VS2005 was installed *after* VA was installed. VA can only detect and integrate its self with IDE's that are installed before it is installed.
In this case all you need to do is reinstall VA.
Of course this does not help with the current problem. Can you try setting the registry key to stop VA loading in VS2005, as described here, and see if that makes any difference?
If you can get VS2005 to load successfully can you then try undoing this registry setting, to allow VA to load, and see if VA and VS2005 now work correctly?