I am crazy about flight sim but had to save to upgrade.  I went from a 466 to a 2 ghz system.  Everything except Flight Simulator 2002 is smooth as glass including previous Microsoft flight sims but for some reason 2002 brings my system to its knees.  I tried adjusting some of the sliders but that doesn't seems to help.  Here are my specs.

Intel pentium Celeron 2 ghz processor
ECS P4S5A2 motherboard
Nvidia MX GeForce4 440 video with 128 ddr memory
256 meg DDR memory 2100 (Can add 128mb more)
180 Gigabyte main hard drive (!7 and 10 gig as backup)
Soundblaster PCI 128 bit card
48x cd-rom  drive
Windows 98 Second Edition 
Direct X 8.01 (Will try upgrading to 9.01a)

I tried downloading the latest video drivers but Nvidia site is not allowing me to download.

It is not the latest and greatest because I've found buying a couple of generations from the latest can save you big bucks, particularly momboard and processor. (I saved more of my money for a honking huge hard drive, believe me, it is nice not to run out of space any longer and full install EVERYTHING) but it should be enough to handle what I can throw at it.

Anyway, suggestion, comment, if anyone has a silimiar system and having no problems let me know.

In a word...........RAM !

I have less of a system than you everywhere but the RAM and I get consistent frame rates avg 30 in Multiplayer mode with me being the host and ALL my sliders pulled to the right......oh except ATC which  I don't deem necessary when just flying for sport with friends...........

Cheapo ECS K7S5A Pro board with 8 USB, and 2 USB 2.0
AMD 1800 XP processor
512 MB of DDR
GeForce 4 MMX 440 -- 64MB DDR
40 + 17 gigs of space
350 Watts of power in new case
48x CD reader
48x24x48 RW
Saitek X-45 for flying