Vdub/Nandub causes my computer to hang at times

[WhyBee]

I'm beginning to get annoyed with the situation. I encode anime using Nandub and Vdub. There are times where my computer never hangs on me and times where it just locks up. When it does lock up, I can't do anything except move the mouse around, I would click the mouse button a few times, then my PC would beep once, completely locking up my system. Sometimes I can do whatever I want while I encode and it'll never hang, other times I would reboot my system completely and not start anything up except for nandub and it would hang. I have no clue what causes it. I usually encode at NORMAL priority, but even set to anything lower still causes it to hang whenever it does. My only guess would be something is overheating or my PSU isn't strong enough. I can't really blame my CPU or Vid card (or can I?) because it would happen when I had my 1.4 t-bird and GeForce2. Currently I have an XP2100+ with a radeon9700pro. I'd say the only things that are the same from the previous system is the same MOBO/Power Supply Unit/RAM. If it makes any difference, here are my system specs.

Windows 2000 Profession SP3
Asus A7V-133A (VIA KT133A chipset ) (Tried with and without various versions of the 4in1drivers, no difference)
Amd Athlon XP2100+
512 PC133 SDRAM (generic brand)
ATi Radeon 9700Pro
SoundBlaster Audigy
Artec DVD-ROM 16x
LG Burner 16x10x40x
Western Digital 120gb 7200rpm
Maxtor 60gb 7200rpm
Maxtor 40gb 7200rpm
Generic 300w ATX
Realtek 10mbit NIC