tizijoan wrote:
the computer got a virus called "buildathome".
There is no currently known malware by that name that can impact OS X. Even the references to possible Windows malware seem to indicate it's something else.
Please take the time to describe exactly what you are seeing in what application, etc. rather than jumping to any conclusions about what is causing it. We can all be of much greater assistance to you if you do.
If I had to hazard a guess I'd say you are suffering from browser redirecting, in which case you will probably benefit from reading Eliminating browser redirects and advertising.