Windows stuck at the "Welcome" screen after login

For the registry cleaning:

• Many of us on the forums actually do not recommend automated optimization tools for Windows 7. Windows 7 does a much better job of handling its own optimization than its predecessors did. We especially do not recommend registry cleaning as an "optimization" step because automated registry cleaning causes more harm to the registry than it actually repairs.
  
  In the future, if you need help optimizing Windows 7, please post a thread in Performance & Maintenance - Windows 7 Forums or follow the tutorial enclosed in that forum to Optimize Windows 7.

Hopefully the damage has not already been done by the registry cleaning. I realize you were trying to repair the system, but you may have made the problem worse. The first step I would recommend is to Troubleshoot Application Conflicts by Performing a Clean Startup. It sounds like you may have already cleaned up the startup items, but you probably did not disable all non-Microsoft services.


If you need further help after those steps, please upload your msinfo32.nfo file. To get this: Start Menu -> Type msinfo32 into the Search programs and files box -> When it opens, go to File, Save -> Save as msinfo32.nfo and save in a place you will remember -> Let it finish the process of gathering and saving the system info -> Right click the .nfo file, click send to compressed (zipped) folder -> Upload the .zip file here.

Also, please fill in your system specs in your profile and not in a post in this thread: System Info - See Your System Specs