Windows XP Pro 64-bit 'net connection woes

[Buffmaster]

Ok, currently running two hard drives, one that's running on XP home and a new one that I just loaded XP Pro 64-bit on. After going thru some small headaches in regards to moving stuff around and copying files and whatnot I tried to get onto the 'net to download new this-&-that but couldn't do it. Logged back over to XP Home and dl'd the newest 64-bit drivers for my mobo, SP2 and a few other things. Logged back over to the 64-bit OS, installed SP2, installed mobo drivers yet still no internet detected. It's an onboard LAN on my MSI K9N4-SLi mobo and works fine with the 32-bit OS, but the 64-bit's not even detecting it. What am I missing here? I shouldn't have to flash BIOS, nor do I think there's any setting within BIOS what enables/disables the LAN depending on 64-bit/32-bit. I is getting frustrated here.