I had to literally scrape it off. It took me almost two hours to clean it.
That client will forever be on my mind. I did a huge favor for her. I gave her a PSU and fan free. I shovelled out her computer. I reformatted and reinstalled everything. I gave her a new drive. I charged her a fraction of what I would normally charge because she didn't have a lot of money, was home bound and the computer was her only source of contact with the outside world. Normally I would tell them to dispose of it and sell them something else.
A day after I delivered it to her, after waiting a month to be paid, she called me up, threatening to sue me and call the Better Business Bureau because she couldn't figure out how to get on Yahoo.
Interesting how it's always the ones you try and be good to that treat you the worst.