Motherboard needs replacement.How expensive is that,generally?Is it a huge deal,or can I do it myself??TIA?

Changing out a motherboard is a tough task if you've never done it. Since your Gateway is so old, you may have a tough time finding a board that will fit into the case. Gateway's are set up in a different configuration than most modern boards. This would mean you'll need a case too, with a power supply, as your old Gateway P/S won't have enough to run a newer board. Then you'll probably need RAM too, as a new board will have DDR or DDR2 RAM. I suggest buying a barebones and use some of your old parts.

I just replaced the motherboard on an old DELL. Never did it before. It was not easy because things never match up right with connectors and cases, etc. I learned a ton of stuff from the internet and the good folks on this website. If you are lucky enough to find a good replacement for your board that has documentation, it is doable. I had no documentation for most of it and really had to dig for it. It took me about a week, but I got that thing up and running. If you are tech-minded and can troubleshoot problems, you can do it.

anywhere for $150-250 u can do it urself but if u have warranty i suggest u use it it is very hard to change

you could buy one off a auction fairly cheap... heres the link http://www.andpcs.com./

try www.frys.com or www.tigerdirect.com