My computer recently sustained damage because I wasn't using an uninterruptible power supply (UPS) and we had a momentary power outage.

Does anybody have experience with calculating the wattage needed for a UPS? I just need the UPS for my monitor and computer.
---My monitor is listed as having power consumption of <105W.

---My computer's power supply unit (PSU) is a 450W.

---Does that mean I need a UPS of >555W? (105W + 450W) (I'm considering this one.)


BTW, the damage my computer sustained from the power outage is that it won't turn on anymore. I'm hoping replacing the PSU will fix it, but I don't really know much about this. I do know I'll be unplugging my harddrives before I test the new PSU: http://wtf.videosift.com/talk/So-what-makes-a-hard-drive-light-on-fire


Thanks in advance if anyone can offer advice!