Hello, I have heard some Dell computers use a proprietary power supply, and I was wonder if this is true for the Dell Optiplex GX280 Small Desktop. I would like to upgrade the psu, but do not want to buy a psu which will not work in the computer. If I can not buy a regular ATX psu, can you tell me where I can get a power supply which will be compatible with my PC? Thanks!Replacement For Dell Optiplex SX280 AC Power Adapter Plus Cord for OptiPlex Ultra Small Form Factor (USFF) GX620, SX280, 745, 755, 760.220W Dell OptiPlex SX280 USFF adapter Charger.For Dell Optiplex SX280/755/760 DA-2 AC Adapter Power Supply, enjoys 1-Year Warranty,60-Day Money Back!Brand New Replacement For 12V 18A 220W Dell Optiplex SX280 Ultra Small Form Factor AC Adapter/Power Supply/Charger With Laptop Cord.The Adapter is a 220W rated power supply and replaces Dell OptiPlex SX280 adapter. Designed to meet Dell's original specifications. The Replacement Dell AC Adapter is designed to be 100% manufacturer compatible and will meet OEM specifications.Always put first the DC output plug into the laptop's power jack before putting the input plug on the power outlet. This is the correct method.Keep your adapter in a dry place with room temperature. Just like other electronic devices, adapter can get damage cause by high temperature.Avoid the metal tip of the adapter from getting in contact with other metal objects because it can cause short-circuiting. Your laptop might get damage when a short-circuited charger is used.Welcome to replacement laptop AC power adapters online store.Replacement Dell Laptop AC Adapters and Power Supply for Notebook Computers.Replacement laptop AC adapter is guaranteed to meet or exceed original Dell laptop AC adapter.Full 2 hours burning test; 3 times quality check and 2 times drop test by QC before package.Warranty and Guarantee: 1 year warranty, 60 days money back.