Dude,
Each time you're playing with video cards that have a hard time watching an HD movie.
First time on a 7100 (g3D mark 31) then on a built in on a 8 year old G41 motherboard, most likely a GMA X4500 (g3D 60).
In my house there is a PC with a decent CPU but a 9300GE (87) its not worth installing PR to see.
My laptop has a 9600M GT (277) and on HD at low/medium settings I can go as low as 15 quite often.
BF2 original specs asked for a Nvidia FX5700 minimum (39) but PR, especially after v1 with all the smoke and fire effects, is waaaayyyy above that.
IMHO a 9800 is about the minimum in Nvidia line to enjoy PR, I am getting a cheap GTX560Ti as it seems a great DX9/10 card for quite cheap.
My advice would be to scan ebay and other ads, go to the dump check out any computers dumped anywhere and you will probably find a card somewhere that will be able to let you play higher FPS. Just watch out for the power supply as gaming cards, especially old ones, use alot of power.
9800 100W CPU needed 400
GTX280 236W CPU needed 550.
Even a new
630 ( 738 G3D) is only euros 50, and I
believe (untested at your own risk) it'll run PR at low/medium at decent FPS, and is so economic with power you probably can keep your existing CPU (25 to65W).
The good news is that Core 2 duos are still great for PR and you can find faster one for peanuts that just drops in but don't forget thermal paste.....