Is there ANY possibility of getting a complete make and model number? Because after the motherboard answer we will then have to move on to the PSU which is aka the PSU. We will get the wattage but that won't really help. We need the make and model of the PSU as well. Dell LOVES the word proprietary. They make the oddest shaped PSUs so that people can only buy their PSU for their exact PC.
PC Make and model?
Motherboard make and model using the aforementioned program OR
https://www.piriform.com/speccy/download
PSU make and model number. Compatibility depends on a lot more than a CPU.