windows - Graphic corruption followed by message: "Too many 16-bit programs are running"

For reference here are my system specs:

• Cooler Master Sniper Scout tower


• Intel Core 2 Quad Processor Q6600


• Intel G33 Motherboard


• 6GB DDR2 RAM


• Radeon HD 4870 GPU


• 1TB SATA Drive 7200 RPM


• OCZ ZT Series 650W PSU


• Windows Vista 64-bit Home Premium

I'm having an issue where at certain times my display starts to become corrupt, with artifacts appearing. This might happen while playing a game, but it can also happen without using any CPU or GPU intensive applications running. I then see the error message from Windows which says Too many 16-bit programs are running. Then the display becomes completely corrupt and I have to shut my PC down. I wasn't even aware that I was running any 16-bit programs, I'm honestly stuck if anyone can help me out here.

Update 1, I've run a:
Virus Scan
Spybot scan
Furmark Test
Windows memory test
Video card memory test

...and all of them have come back with no problems.

Update 2:
When my PC is idle there are about 55 processes running and 6 icons on the right-hand side of the Windows taskbar, and the CPU is at 1-4%

Also when idle the system's GPU and CPU are approximately 45^oC and all other measurements hover around 25-35^oC. When under load, all temperatures stay basically the same except the GPU which goes up to about 60^oC.

And yes all of the power connections are installed correctly.

Answer

I replaced my graphics card and the problem has completely resolved. There must have been some short or damage to the actual hardware itself.