Windows 7 User Login Lag?

So I just upgraded my 64-bit vista to windows 7, and everything works smoothly except for one thing. Logging into a user takes an average of 20 seconds just to show the desktop and then another 10 or 20 seconds to load everything. Now there's a similar problem on forums where this happens if you have solid color background but in my case I'm running an aero theme. The first time after I startup I log in its the regular 20 seconds, but if I log out and the back in its around 3 seconds which is normal logging in time. Please help its getting really annoying!