I just started playing this game on a refurbished laptop. I had to download 3d analyzer to get it to run. When I first started playing the game ran in slow motion. After some graphics options tweaking I got the game to run normally. When I made it to the second world first stage "Opera House" the game runs incredibly fast roughly 2x the speed I was getting. I tried looking at the forums and haven't found anything that works. I tried the ctrl+alt+delete for the affinity but I don't get that option. The only thing I get is speed priority. Also I don't know if this helps but here's what I get from DxDiag, not sure if it helps.

Operating System: Windows XP Home Edition (5.1, Build 2600) Service Pack 3 (2600.xpsp_sp3_gdr.111025-1629)
System Manufacturer: Dell Inc.
System Model: Latitude D610
BIOS: Phoenix ROM BIOS PLUS Version 1.10 A06
Processor: Intel(R) Pentium(R) M processor 1.86GHz
Memory: 1016MB RAM

To me that sounds like the dual core issues some processors have. Back in the time when Painkiller was made dual cores weren't really around so the engine doesn't support them, causing certain models to mess up with the game speed.
But looking at those (incomplete) specs you gave us, I'm not sure whether that's dual core at all. Are you sure your computer is up to the requirements of the game?

What all do I need for the specs? DxDiag gave me way too much info. The first world (the first five stages) worked fine, sure I had to nerf the graphics but that doesn't bother me. If the first world worked wouldn't that mean that my computer meets the minimum? The videos work fine, so does everything else.

Just checked the requirements for the game, and your computed does indeed match the recommended specs. Judging by the memory you probably don't have dual core, so that can't be the issue either.

I'm out of ideas there, best you can try is backup your saves and re-install. Since first chapter worked fine it could be corrupted files. By the way, does the first chapter still work as it should be or is it bugged as well?

Well, I had the slow motion effect problem that many have. All I had to do was to turn down the graphics. The problem stopped after I turned off bloom, I think that was the biggest problem. Other than that though I didn't have too much trouble. I'll try to re-install it again, maybe I messed it up. I am using the dvd collection of Painkiller I don't know if there were any problems with it though.

Game is running in weird ass slow motion for me. I turned off all graphics settings, didn't effect my frame rate at all (showfps 1 = never gets below 70), game still runs in super slow mo. Its not choppy its just slow motion.

Switched to task manager and tried running on a single core. Didn't effect the frame rate, didn't effect the slow motion.

Tried compatibility modes, it either crashed or didn't effect the slow motion.

None of the suggestions I've seen for this problem have worked at all for my nvidia 9600 & core 2 duo.

I know I've had the game running well on this exact same machine once before. My last option is to reinstall and ignore the patch. Maybe that'll work.