That depends.
In no case have I had to wipe data, but as in this case I sometimes have to wipe Windows which can mean hours of software reinstallation and sometimes it is not possible to find the original media which makes for more difficulties.
If it's something new I haven't seen before I'll spend quite a few hours trying to beat it. I proabably spent 10 hours on this machine. This is a "continuing education" cost and if I can beat it, it'll be easy next time. Very seldom have I had to call it quits.
If a machine is absurdly infected (many home computers) I'll just wipe Windows right then and there. If it's a business machine it's usually not that bad - unless, as in this case, it's been used to play music.
If I do a machine in the field, which I strongly discourage, I charge by the hour. If it's brought to the shop I charge a flat fee which may be anywhere from $40 to $160 depending on severity. If I pick up and deliver there's a travel charge. Any work for reinstalling software, setting up the network, etc. is hourly. It can get pretty expensive.
The Los Angeles Times did an article a few months back about people who no longer use the Internet because they can't afford the cost of cleaning out the scum. Apparently the stores around here charge about $300 to $350 to just wipe the disk and reinstall Windows - all data lost.
