You can check original Pavel Vladov page (http://www.pvladov.com/2012/08/windows-7-stuck-on-welcome-screen.html) or simply do as described below.
Why I'm copying that? Just to find problem solving solution quickly when it appears again.
So in order to solve the problem, you should find the problematic software first. Restart your computer and keep pressing F8 until you get to the Windows 7 Advance Boot Options screen. Then select one of the "Safe Mode" options and press Enter. On the log in screen enter your password and Windows will start in safe mode (i.e. it starts with only the most important drivers and services loaded). Here's how I found the problem and fixed it, the procedure should fix your problem, too:
- Click the Start menu, enter "msconfig" and hit Enter
- On the General tab click Selective Startup
- Clear the Load Startup items check box
- Click the Services tab, click Hide All Microsoft Services to select it and then click the Disable All button
- Click OK and restart your computer
When you have removed or reinstalled the problematic software and the issue is solved you can restore you computer to start as usual by doing the following:
- Click the Start menu, enter "msconfig" and hit Enter
- On the General tab click Normal Startup
- Click OK and restart your computer