"Windows 7 customers hit by service pack 1 install 'fatal error' flaws"

apparently this only concerns pre-installed OEM systems… so the majority ;D
http://www.theregister.co.uk/2011/03/14/microsoft_windows_7_sp1_fatal_error/

http://social.technet.microsoft.com/Forums/en/w7itproinstall/thread/cad66cc7-9912-4cbe-898f-ad8ff9344308?prof=required

ps: this said I got Win7 here installed on two systems, one pre-installed, and I haven’t seen the issue happen.

workaround here:
http://support.microsoft.com/KB/975484