BleepingComputer.com: IE-7 shuts down computer.

My computer has developed a couple problems in the last while. Recently,when I'm using IE-7 and I click on something a little error message pops up, titled "Isass.exe System Error". Below it,it says Object not found. If I click on the OK below it,or click the X to close it,the whole computer shuts down rapidly.
I have no idea what this cryptic little Windows message means(Curse you Microsoft!!-at least they could make these messages say something intelligible),and I have no idea how to fix it,and it's a bummer losing data..
Can anyone please help?

This post has been edited by hamluis: 11 January 2011 - 09:22 PM
Reason for edit: Moved from XP to Am I Infected ~ Hamluis.

Someone led me to a 5 year old thread that said the Isass.exe was the Sasser worm. I looked for a Sasser removal tool and in Google searches found some of the removal tools were 5 years old too,Sasser must have been prevalent back then I guess. I downloaded 2 removal tool(Sophos and Symantic) but I decided to run my Norman Malware Cleaner Tool first(When all else fails it saves me almost every time). Norman found an old infected program(About 5 years old,but I downloaded it recently)with what appeared like the Sasser worm. My Malwarebytes,Avira,Spyware Doctor that run routinely had missed it.
IE-7 is running fine now.

Thank you for letting us know.

Orange Blossom