A shit computer? Yeah. It's very picky about what it wants to run, too.

Can you run Unreal Tournament 2004? If so you've got some good options available to you there. Out of Hell is a pretty polished single player zombie mod.

Unfortunately, no. I think I tried playing it too. Unreal Engine 2 seems to hate my computer. The first Unreal Tournament works well though. Any for that?

Possibly. There is a massive ton of mods for that game after all. You could try consulting moddb. If nothing else, you might find something else that interests you.

Yeah, I love Moddb. I was checking there for a good CS:S zombie mod, but they seemed to either be like Zombie Panic! or require you to do all sorts of weird stuff that may or may not work since they've ported everything to a newer version of Source. I didn't see a zombie mod for UT on there either.

My computer does the same! As Navagon said, moddb would probably be your best bet.

I don't know what this one is like, but see here : http://www.moddb.com/mods/zombie-master-black-edition/downloads/zmbe-12e-full-install-windows

I am unable to run HL2 on my pc, so I can't test it. ;-(

Mmm... Zombie Master. I've played the standard version. It's multiplayer only, unfortunately. Also, I have heard nothing but awful things about Black Edition. I would suggest playing traditional ZM though, even if you only do it once.

No, I cannot play 'Traditional ZM' because, doens't it need HL2?

EDIT: see here http://www.moddb.com/mods?filter=t&kw=Zombie&released=1&style=def&theme=def&game=61&type=def

EDIT 2: Shotgun FunFun might be ok, as long as you don't mind it being 2d rather than 3d :http://sandbox.yoyogames.com/games/63494-shotgun-funfun/send_download?code=40b17698cf16c08ce440b2f2b8f439de9a186496

Yeah, it does, I was jsut suggesting that if you ever get a chance to, try it out. Also, I had the same idea. One thing I don't like with Moddb, the two search bars don't do the same thing.