ASP.NET upgrade seems to be taking a very long time to start

At work I'm tryhing to upgrade an ASP.NET 2.0 app (which we wrote using VB.NET 2005) to ASP.NET 4.0. I had a few problems during the upgrade, but eventually worked them all out. At the end of the day I decided to give it a quick compile and see if I'd get the start page, so I hit F5 in VS 2010. I left it that way, and man was it acting weird. VS 2010 wasn't responding to anything. If I hovered the mouse over VS 2010's minimize or close buttons, in the upper right corner, then those buttons were flashing very rapidly. I'm not sure what was going on. After waiting 15 minutes to see if it would come up, I decided to try clicking on the close button. Nothing happened. Eventually, I had to le开发者_运维百科ave (I take public transit, and I have to leave when the bus comes), but I thought I'd leave it going as is, in hopes that it might fix itself.

But what I want to know is this, is this pretty standard behavior? Does it normally take this long to do this? This website is of modest size (<100 pages).

(Later) When I came into work today, 8 hours later, VS 2010 was still doing whatever the heck it was doing, but basically it wasn't responding to anything.

That's not normal at all. Something is wrong, but I can't guess what. I've been using Visual Studio 2010 for several months now, and while it has occasionally crashed on me, it hasn't done what you describe.