This may be out in left field. But, Correct me if I am wrong here guys and gals. But he said he is using XP. Why can't he use his help and support stuff and run a system restore. After which he uninstall this p2p app. Update his AV, and any patches that maybe lost due to the restore. Technically wouldn't this remove anything he hasn't added?

I realize this would not fix his security issue if in fact it was compromised. But it would be a good place to start. So he can get back online and download some tools localy for further tests.

Be sure you have some boot disks made for the pc prior to a restore. Make sure they have the drivers for your cd rom also.

Be safe and stay free