IM not the only one who have problem like this...
Yes, Its clean instal, Dl'ed from microsoft directly, Win 7 RC 1, activated, ready for updates ( up to date ), and everything is working normal, but when screen saver is on, and after moving mouse I dcan t see taskbar, and I need to log off and then when I log in I can see it. But there is another way, just to run again screen saver, and theres magic taskbar is up again.. But I found solution... TURN OFF SCREEN SAVER
Problem solved