Painfully Slow Start--with Strange characteristics

Hi

I'm running Windows 7 Home Professional on my Dell Laptop. I've limited my start services to Windows, Fences, and Avast Free. Start is terribly slow--Up to login not too bad, but after I've logged in, the taskbar loads and absolutely nothing else happens until I double click on the desktop. Then I get an error message that MS Windows is not responding. When I end the process, the taskbar reloads and after a short delay, my fences and icons open up and the start sequence slowly comes up.

Bizarre and there's obviously something wrong--does this ring a bell for anyone?

Thanks