Hacked yahoo account sending eletronic merchandise advertisements

Hello Major Geeks,

My Yahoo account has been compromised by one of those viruses that sends messages advertising electronic products to everyone in your address book.

I know that there is a strict policy at Major Geeks of running all of the Malware removal steps before requesting help. I have done so in the past and always been helped. Also, I have recently downloaded the latest advice and plan to carry out the steps on my new computer, a Lenovo running Windows 7.

The only problem is that for this email account hack, it's difficult to know which machine I should run the steps for. I have two home computers but I also use a school computer. In future, the best solution might be simply to avoid checking my Yahoo account on the school computer, although I would have thought their security would be superior to that of my home computers.

Anyway, for now I would be very grateful if someone could help me by telling me what information I need to post and what basic housekeeping I can do in the meantime.

Also, sorry if there's already a thread about this specific problem somewhere else on the forum. I did run a few searches but couldn't find anything.

Thanks!