Windowblinds No Sid Change HELP! HOW DO YOU REVERSE AN SID CHANGE IN YOUR VISTA PC?

HELP! HOW DO YOU REVERSE AN SID CHANGE IN YOUR VISTA PC? - windowblinds no sid change

I wanted to install WindowBlinds Act and the instructions said I had to change my SID PC at work. The field "SID ..." took 5 hours, so I thought that the expansion and ends with the Task Manager. The instructions say, if I closed without completing the process leading to an unstable system.
Everything seems to work even after the break ... Exception, all files and programs installed on my computer had been deleted and I do not have administrator privileges. Moreover, if the administration appears privileges asked for a password, there is / no / place to set the password and can not be everywhere.

I have not backed up my files first.
I'm too old SID of the computer.

This is a very sad case. I think the best thing to do, can I bring back the old SID. I have written to a file in Notepad, but with everything else, was abandoned. Help?