Networks modems stopping computer powerin up

ok heres the problem. Today I bought a Mentor ADSL pci modem got it home and put it in my comp pressed the power switch.
Nothin. Wouldn't power up. I took the card out and pressed the power button. PC's workin again. shut it down put the modem in a different slot and try switchin on again.
Nuthin. OK my modems b0rked methinks. nope i tryed it in my old system and it works fine. hmmm. maybe its drawin too much power ( i have almost no cards in me old pc) so back in me decent PC i take out NIC and put in me Modem. doesn't power up.

thats it i cannot think of any more reasons why my pc shouldn't power up, but every time I take it out the Modem it works fine. i cant find a manufacturers website or anything useful in google to do with this problem.

some comp specs

Mobo - gigabit 7dxr
CPU - 1GhZ
Ram - 512Mb
GPU - 3d blaster geforce 4 4200ti
other bits, audigy 2, 20gb+8gb HDD, NIC, PCI 56K modem(at the mo neway), DVD-CDwR combo drive. OS - XP pro

i appreciate ne help
cheers in advance guys

 

Maybe it's not compatable with your board?, I had a gfx card like that which I wanted for a htpc in the end I had to buy a cheap mobo to use it in. The card would work in 4 mobos out the 5 I tested but the one I orignally was going to use.