for some modern demanding games. All IT gears will be out of dated in a few weeks/months time, just get the right stuff for the job you required. Good graphics cards are very expensive, but I think 9600 card (£66) should be fine.
Regarding the FarCry demo it could well be your graphics card, this game needs a very high spec to run (especially in the graphics department) but even though your card is reasonably old by todays standards I can't understand why your having trouble with FS2002 it works with almost anything and its quite an old game now I think its even on budget now. The only thing I can think of is the setup isn't right somehow. How about NGEs suggestion? Just remembered something, and it may not be this but, a friend of mine bought a new board and processor last year and used his existing hard drive which was about 3 years old and he found that there wasn't much speed difference in a lot of games. He bought a new 7200rpm hard drive reinstalled everything and it was amazingly fast. Can't say for certain that it was the hard drive as he may have inadvertantly installed something wrongly the first time round.
I have an XP 2800+ Barton in my desktop (ABIT AT7 Max2 MOBO)and a Pentium 2.8 in a sony vaio laptop. Both have 40 GB hard drives and 512 RAM. The Athlon is noticeably quicker than the Pentium. It's also noticeably quicker than my old Athlon 1.4, so it sounds like you may have a problem with your setup. Have you checked the settings in the Bios as NGE has suggested?