cannot install onboard realtek audio device

I am not able to install onboard realtek audio device on my system.
Profile : mother board elite P4VMM2 with built in realtek ALC 655 chipset, win2k sp4.
What happens: I tried to install the driver wdm_a373.exe, wdm_a372.exe,wdm_a352.exe and I got the following messages:
"Cannot load the Realtek Audio driver. The driver file may be missing. Try installing the driver again or contact your system adm." and then
"An error occurred during the installation of the device. The handle is invalid."
The same happens when I use the vendor´s CD.
I have adm privileges on the system.
I have already tried to do that both on safe and normal modes.
The onboard chipset is enabled on bios.
Then I tried to install a CMI PCI sound card and got the same error messages.
Please, has anybody experienced such a problem ?

PS: If it helps, I can send the error screenshots.

Thanks,

Ney.