All who are to update your W7 with SP1 or still haven't, make sure to save your precious files to an external USB/Disc or make a full system backup before doing it. It almost fucked up my whole hard drive, because I have OEM version (comes pre-installed on new laptop) and couldn't run a repair instllation. One of system folders got corrupted/unreadable after the update and luckily, after hours of restarts chkdsk (check disc) managed to restore the corrupted files. Not even safe mode worked and blue screen would prevent any boot attempt.

So yeah.. be worried.