Previous answers are good.
But in case you insist on using IE, switcing back to IE7 is simple: Uninstall IE8, then reinstall IE7. Unless your system has been corrupted, this should go along fine.
My opinion on the problems you're having, I agree with the 1st technician. IE8 should be fine long as the system is not corrupted.
More resources: Computer Security Software and Download Antivirus .
