Installed Bd 2011 Next Day Comp Wouldnt Boot

pretty much as the subject states, installed 2011 internet security and next day the it just wouldnt go past the windows 7 logo, system restored to before installation and its fine again.

what confuses me is that l did 3 or 4 reboots yesterday and it was fine. could there be any issues between security essentials? as l had not had the chance to uninstall at the time?