Changed the PSU. If you are changing cases also, there is no issue at all. Gateways have ATX motherboards. If you are using the same case, then it's kinda hit or miss. With their small (mATX) cases, a regular mATX PSU will fit, but the vents and fans will be on the wrong sides. A standard ATX PSU will fit in a larger gateway tower, but the screws won't line up. The one I did in the latter type had a tooless mounting solution in addition to screws, which is all I used.