Area-51 R2, no power

@Cass-Ole​ how do you go about checking the voltage of the CMOS? 

@Roamingrook​ The service manual reference given by @Cass-Ole explains how to remove the CMOS battery. Then with a volt/ohm meter and set on DC voltage touch the bottom and top of the battery at the same time as seen on this YouTube video.

@JOcean​ I found a new battery as I do not have a tester, replaced old cmos and still have the same issue is there something else to it

@ProfessorW00d​ thank you I happened to find some in my house. Replaced old cmos for new. Nothing has changed any further ideas.

@Roamingrook​   test your PSU   Built In Self Test

@ProfessorW00d​ I will try this later as I am at work right now, worse case scenario are there any fixes for the faulty PSU and or replacements I could buy? Either dell or third party

@Roamingrook​ Are you sure they were brand new and up to date as they do have best before ratings and over time can weaken. Also leave the old battery out of the system for 15 minutes before installing a new battery.

@Roamingrook​    first consider recommendations from JOcean and make 100% sure the CR2032 battery is new, and not something that has been sitting in a desk drawer for years.
If the PSU fails the BIST, and you are considering replacing, the easiest route would be to replace with the exact same type Dell Alienware PSU that you already have in your R2. That way you could leave the existing cables in place. The R2 PSU is standard ATX format, so a 3rd party PSU is an option, but would require replacing all of the cables, some of which are of particular lengths and configurations.