Viruses are the most difficult to filter out. It takes a lot of time for the filter to recognise them, whereas others such as mp3 spam it only takes one or 2 times before the filter has learnt to recognise them.

As suggested earlier, arrange search results by size. You could also try checking with Bitzi to see if there's any user-feedback on the file. Some programs are reported to bitzi.

Depending on the program you're after, just make sure it's very large in size. Look for the maximum sized one. That's if anyone is sharing it. Vary your search, try at different times. People all over the world use Gnutella & sign on & off all the time. So new files become available at different times or days or weeks.

Another alternative is to buy a mac computer & then you don't need to worry about viruses, etc.