Hey there, i purposely joined just to reply to this.
I've recently bought a copy of The Sims 2, and yes . . . i have had the same DirectX 9.0c problem as many other people. I have installed the latest driver for my graphics card.
If you can help any further this may help, i found it in the run command "DXDIAG":
DEVICE:
Name: 3dfx Voodoo3
Manufacturer: 3dfx Interactive, Inc.
Chip type: 3dfx Voodoo3
DAC type: 3dfx Internal DAC
Approx. Total Memory: 16.0mb
Current display mode: 960 x 720 (32 bit) (75hz)
Monitor: NEC MultiSync XV15+
DRIVERS:
Main driver: 3dfxvs.dll
Version: 5.00.2489.0028 (English)
Date: 17/08/2001 15:55:58
WHQL Logo'd: Yes
Mini VDD: 3dfxvsm.sys
VDD: n/a
DDI Version: 7