I had the same problem.

Only for me, it was a NIC and a USB KBD and mouse.

I know you said it works if you REMOVE the modem, but have you tried the modem in different PCI slots?

If I remember correctly, the USB shares with slots 4 and 6. I may be wrong so you may want to check the unofficial FAQ yourself (an essential read for KT7 owners).

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Hey. What kind of party is this? There's no booze and only one hooker. -- Bender (Futurama)