I have a win7 also, and when I try to open the wind its getting stucked at the welcome screen..
what I did:
I tried to make system restore but I couldnt coz I didnt do a restore point before.So, I went in safe mode with network but I couldnt connect on internet so, I just saved my files into a hard disk.
I tried then to make a system recovery with the F11 but after I press the button the screen says windows error and again the same choices lke, safe mode etj... after I dont choose anything is asking me for the password and after that the screen stuck at the welcoming even for 12hours...
just for the records,
before those happens when I wanted to run my pc after inserting the password the screen was just black.. with only the mark of the mouse.