File Transfer Lock-Ups

I have a Win98 Se machine currently with a netgear FA310TX NIC. Everytime i try to transfer files to or from the computer my machine locks up. And to make things stranger, i have a proxy server running on this computer and it will still pass packets with no problem. I’ve reloaded windows, reloaded nic drivers, tried disabling every program possible, tried 5 different brands of NICs (3 PCI, and 2 ISA), and different slots on my motherboard with no change. Any suggestions are helpful.