You know all the commercials about how second-hand smoke are bad for people? Got these from a colleague online. Owners smoked at their computer for years. I've dealt with a few PCs like this over the years and they're next to impossible to get clean (and you don't want to pay for the per-hour that it takes, trust me). The smell never leaves them either. A machine this bad (uncleanable and fairly old), I'd be tempted to recommend a new PC and transferring the data/docs over.