Buying new "everything" after a power spike(?) fried it all

+1. VA is a try at appearing large, but it is a fudge.

The W rating of the UPS just has to exceed the peak possible power drawn by all devices connected to it. If the W rating ever gets exceeded, the UPS will shutdown immediately, which, when using a line-interactive UPS running off the battery, will mean the computer will lose power straight away, which may cause loss or corruption of session data.

no way 280W is correct
you left stuff out big time.
there is not a system today that would get by on 280W
500W is the very minimum I would ever use in a build.

Even when I added on the graphics card, the max I was getting was 342W out of that calculator…not that it matters…I wont be getting anything less than a 650w PSU anyway