zombies.. (instant infections from server network)

SO... I started a new job, and I was piecing together pc for myself. I installed Win2K and popped on an ehternet cable after reboot. (no service packs yet) within 5 minutes my computer was infected with no less than 7 spy/maul/theifware programs - slowing down the PC and eventually crashing it. (its not the fasteset thing on the planet) So, my question is, WTF? I have a plan to eliminate most of the problem soon, though, does anyone know or have experienced this before? Previous job I had was set up the same way, only internal IPS (192.168...) this network at th enew site is all class C.

Anyway, thats my welcoming committee for the new place

Any similar instances would be cool or your thoughts.