If you do a Google Search on "Hackers.KeyGen" you get gobbledly gook, lots of it in non-English, a lot of it random words on the page. I didn't follow any of the links, for various (obvious, I hope!) reasons. The discussion Louie Ray started here is about 5 on the list.

Symantec doesn't know what it is. "No results from your search."

Search on "keygen" and you'll find it is a program that generates key codes to access programs. You know those long strings of letters and numbers, often grouped in fours, that you enter to access a program? That seems to be what the programs are for. To break into legitimate programs with illegitmate keys. And hackers are the folks who do it. http://www.keygen.ms/ is a site that lists all sorts of programs it generates keys for.

Another site says

Hackers Crack Serial & Keygen
Crack Serial Keygen is a search engine that gets searches all of the major crack, serial and keygen sites so you don't have to visit them all manually!
Try avoiding searching for: crack, serial, keygen, warez, full, iso, download, 2007, key, release, ddl, usenext, cracked, .rar, .zip

Not sure what you had on your computer, or what you downloaded to get it. And I'm not sure what your friend thought he was doing. Maybe this is a virus that works by stealing key codes from compromised computers. A search on " 'hackers.keygen' and virus" brings the mudcat thread to the top and little else.

While searching I stumbled upon some interesting forums. this guy has something that is apparently nothing that he was trying to remove. They're sending huge registry files back and forth to examine for problems. I see a list of all of the programs he has installed--it's like peeking into his underwear drawer or medicine cabinet. Otherwise private stuff. :)

SRS