If it's still in it's original tower that's a whole new ball game. You seem to be suggesting that you will simply leave everything as is, switch it on and let it boot up in Windows 98 and then connect your existing PC to it. Is that right?

Yes you can do that and you would need a Network Interface Card (NIC) in each PC and an ethernet crossover cable. You would then need to put both PCs in the same Workgroup and setup file sharing on the Win98 PC. You would also need to allow access to your PC through your firewall.

I have to say it would be 10 times more efficient to remove the hard disk from the Win98 PC, install it yours and the use it as a slave hard drive.