Brains are fun to use! So let's try it...
Fact number 1. Lets see, the 8800GTX is a pretty darn new card with a heck of alot of power.
Fact number 2. AGP is becoming old and I don't believe manufacturers are really even interested in AGP anymore since PCI-E x16 seems to dominate the Gaming and GPU world.
?Fact number 3. I don't think they even make AGP 8800GTX's after I did a quick google and newegg search.
Conclusion. So if he is upgrading his GPU, as that is all he has listed for information, Then I would have to guess that it is a PCI-E x16, am I right?
Or you can just skip all of that and newegg it and see if there are any AGP versions of the card he is offering, if not, then google it and see if there are any agp versions there. Otherwise it would be pretty safe to, once again, assume that it is a PCI-E x16.
Okay wow, I seriously need to get a job. I'M SO BORED! lol
-SF