I bought a 5 port USB 2.0 expansion card for my aged pc to add to the two 1.1 usb ports on the back. If I plug the network adapter into it only works intermittently, and I've bought an external hard drive which if plugged into the port dies, and the pc freezes until I unplug it.

I can only think that the Bios needs upgrading but I'm too nervious to do it until I've tried everything else. Can anyone suggest a next step?

The mother board is a Gigabyte GA-7DX

No, you don't update bios to use an add-on card. If that's the case, kiss Gigabyte goodbye cuz that'd be the 1st.

I suspect your USB card's chip is conflicting with your hardware or something else. Try another one with a different chipset. Look at the biggest chip on the card to tell the make & model.

A powered USB hub would be the best solution.

Thanks.
I've swapped the card onto another PCI slot so that the ports don't share IRQ with anything else. I thought that had done it, but the network adapter still loses the connection intermittently. Looks like I will have to follow your advice and buy a better USB card - oh bum