Battlefield Vietnam Problem

Hey guys - ok,i got a problem with vietnam - i know there was already a fairly large thread about problems with vietnam, but noone had my problem exactly, and none of the suggested solutions worked. Here we go

I run a gaming cafe, and my vietnam has all of a sudden stopped working. I can load the game, and connect to a server, but after a minute the program dies and im back out to the desktop. I tried changing the setting as suggested from 0 to 1 in that other thread, but that didnt work. Also, another point of interest is that the program will run fine locally - When we run a lan game, there are no problems... Poor graphics card is not the issue i assure you... heres the cpu specs....

Processor : AMD Athlon 64 3400+ w/ 512K Cache
Motherboards : Asus K8V-X, w/ Audio, Gigabit LAN, SATA RAID
Memory: 512MB PC3200 DDR400
Case : Thermaltake VA3000BWA Tsunami Dream Tower, Black w/ Window
Power Supplies : Enermax 485W EG495P-VE SFMA Noisetaker
Case Fans : Zalman ZM-F1 Case Fan, 80mm w/ Noiseless Adapter
Cold Cathode Light 2 : Elite Cold Cathode Kit, 30cm, Blue
Floppy Drive: Panasonic 1.44MB Floppy Drive, Black
Hard Drive: Seagate 200GB Barracuda 7200.7 Serial ATA 8MB Cache
Optical Drive 1 : LG 16X DVD-ROM, Black
Video Cards : Asus AX 800PRO/TVD Radeon X800 256MB w/ VIVO, DVI
Monitors : Samsung 997DF (Pure Flat CRT, 19in, Silver/Black)
Sound Cards : Onboard 6-Channel 5.1 Audio
Speakers and Headsets : Logitech X-120 2-Piece Speaker System
Ethernet Cards : Onboard 10/100/1000 Gigabit Lan
Keyboards : Microsoft Multimedia Keyboard, PS/2, Black
Mouse : Logitech MX 310 Optical Mouse