Open an IRQ

I am thinking of networking my two computers together. When i consulted the company of the network card to see if it was compatible to my computer, they said that i should check if i had and irq open.
I did check and i am pretty sure that i do nothave one open.

Since i use dsl for my internet connection, i was wondering if i could get rid of the built in AT&T modem irq to get an open space.
I am not sure what other item other than the modem to remove.
My question is, it this a good idea?

I would also like to know how i would go through this procedure.

Thank You
-Ammar