Aspire XC-1785 Query reg: 14400W11S PSU upgrade from 180 watt to 500 watt for GPU upgrade

Your XC-1785 uses an ATX12VO design, so has a different power supply than used to be the norm. It provides only 12V to the motherboard, and all other voltage are derived from that on the motherboard. They are needed for some of the newer Intel branding and should be less expensive to build. That doesn't mean they are less expensive to the end user though, since there are only a few companies making them. Yours should have been a 300W, I don't see the 180W supplies shipping with the XC-1785 models, but they might have changed that at some point in the production. They have built 500W OEM supplies that should fit, usually provided in the gaming rigs, so those are an option. With third party supplies you have to do some cabling changes to provide the needed signals to the MB.

Here are the stock supplies shipping with units in the USA:

The supply is not a stock ATX form factor, it's closer to the Flex supplies, and much smaller is physical size. Maybe you should look into a GPU card with slightly lower performance that will run in 300W…