Strangeness!

Hi Guys,

so i just built a new PC with the Gigabyte EP45-DS3P, an Intel C2D E8400, 2 gigs of AENEON 1024, running XP Pro 32bit (SP2).
PC is used for Pro-Audio mostly, so i have a M-Audio Omni-Studio Delta 66 PCI-card and Edirol UM-1 Midi-USB unit, running Logic Pro and FL Studio 8.

Here my problems:
after some time of a new boot, my internet will just disconnect, the modem will still be connected (Alice, Turbolink IAD by Sphairon), but i can't connect to any websites.
trying to disconnect the modem will do nothing, it just stalls so i have to reboot.

around the same time, my whole soundcard-setup will disappear (M-Audio and the onboard Realtek HD), and in sound-devices it shows 'no sound-device' greyed out, so i can't change anything either.

i tried updating my drivers, but there aren't really any new ones right new.
also, i removed the M-Audio with no effect, so could it just be the Mobo?

any help is much appreciated.