Vista X64 Ultimate + DFI LP NF4 Ultra-D + 8800GTX going to sleep is BEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEP

Hi all,

as the subject states......

I run Vista Ultimate x64 on my 4GB, Opteron185 (CnQ enabled) DFI Lanparty
NF4 Ultra-D system with a 8800GTX in it.
All works great.
I've applied all the interesting hotfixes, run the most current NVidia
drivers for the chipset, sata, stuff and 8800GTX.
Games and well, everything fly on this system, it's quiet and cool due to my
CM Stacker case with loads of fans and CnQ.

I'm very pleased with Vista...... except for one thing

I can't use the Sleep function of Vista. When the system goed into Sleep
mode the screen turns black, the power led blinks and my 8800GTX starts
beeping. The beeping never stops, I can't get the system out of Sleep mode,
unless I hold the powerbutton for several seconds to really shut the system
off. After that, the beeping stops and I can switch the system on again.

This is not what I expected Sleep to be

Anyone? How can I get rid of this annoying problem?

Grtz,

Patrick