1 pc 2 network card

i have 1 pc running on windows XP with two network card:
1 nic is connected to a router for my internet connection and LAN.
1 nic is connected to a network printer using a cross-over cable.

everytym i connect the two cables at the same time i can neither connect to the internet or print on my network printer, operation will return to norm if i disconnect 1 cable.

is there anyway i can connect the cable at the same time?

thanks!!!