I have a Sony Vaio recently upgraded from Vista to Windows 7. Working perfectly until yesterday when I went to re-install Roxio Home Creator. Now machine boots up to Win7 welcome screen, but displays Please Wait ... and won't go any further. I changed boot order to external drive (usb), CD, hard drive. Succeeded in getting Computer repair to run (it reports no errors). Can get into regedt32, and Registry repair program from command prompt. Rstrui.exe won't work, as it can't find a restore point (as drive letter has changed - C: is now E:). msconfig won't run as it says I have to be a memebr of the administrators group! "whoami" shows user as NT authority\system. Would be very grateful for any suggestions which would get me past this problem!