I would check newegg for a corsair or antec earthwatts power supply. Haven't found any detailed pics of your motherboard. Check photos at newegg.com and compare the connections to your gateway power supply. Also be aware that your board is fairly old and impossible to replace, so handle your components with care. If gateway has it, the price will be too high. You can also clean up your fans when your case is open. Use a canned air speciality product with special solvents that evaporate quickly. I use "perfect duster" from frys, but many brands are available. Newegg has a powercolor 1 gb ax5750 for $104.99 after rebate. I use powercolor, and have had no issues with it.