I was installing approved software for my new Sony P800 mobile phone onto my laptop which runs Win Xp Home. After installation i had to restart. When I did this, and every time since - The following message appears, " isass.exe has failed" - when i click ok on this window - the computer reboots itself, and the message appears again. This happens every time i turn on the computer - and it wont seem to let itself startup at all. I have tried to boot using safe mode and last known good config - but nothing works. Any1 have any ideas at all? Other than to reinstall Xp / kick it harder?