GeForce 6600 + Windows XP, help with hardware acceleration

Hello Everyone.
This is my first post here.
I've installed latest K-Lite Codec Pack, but I can't force MPC-HC to use hardware acceleration. I've done some research and I found that Nvidia has marketed GeForce 6 series as capable of hardware video decoding, they called it PureVideo. Do I have to install some older version of Codec Pack to use this feature?
Thanks in advance for every reply.
Have a nice day.

That GPU only provides partial hardware acceleration. The only setting that might work is NVIDIA CUVID in LAV Video decoder.

Thanks for the reply.
I've changed the Hardware Decoder to NVIDIA CUVID, but it says N/A next to it, so that's probably not working.
https://i.imgur.com/ErPJZFg.jpg
When I choose DXVA2 it says OK, but from what I read, my card only supports DXVA1. Correct me if I'm wrong.

DXVA2 requires Windows Vista or newer. Windows XP only works with DXVA1.

Try latest driver:
http://www.geforce.com/drivers/results/57493

I've got version 260.99 WHQL Drivers released 2010.10.25 installed. Some time ago I tried some newer drivers, but they caused BSOD when trying to run any game. These are the latest ones that are stable on my PC.
I've tried the drivers from the link, that You've provided, because I only tested newer drivers on games, not on movies. I haven't seen any difference with playing videos, and I got BSOD when I started game Worms Armageddon, so I've installed these older drivers back.
How to see if the hardware acceleration is enabled? On the other PC, I've seen something like "Playing [H/W]" in the bottom left of the MPC-HC.
What videos should I play for testing? I've tried with DVD and The Simpsons Movie trailer, MediaInfo tells that it's: "Format: MPEG-4"
What about something like this? http://www.nvidia.com/object/dvd_decoder.html

You should test it with H.264/AVC video. Yes, it will say "[H/W]" in the status bar when it is working.

Are you actually having performance problems with video playback? Hardware acceleration does not have any benefits expect for reducing CPU usage.