APC ups 540W enough for my computer?

Sorry, I wrote it in my public profile but it doesn't show up here 😀

Here it is:

Corsair 850TX
Core i7 930 2.8 Ghz
Gigabyte x58A-UD3R
OCZ DDR3 Tripple Channel 6GB
Sapphire HD 5850 Crossfire
WD Caviar Black Sata III
DVD
Nox coolbay devil edition

I just want 5 minutes to shut everything down
 
The unit that you selected will not work with an active PFC power supply. You are right that the Back-UPS does not out put a sine wave. You need to get yourself a minimum of an APC Smart-UPS 750VA LCD. This is the smallest unit made by APC that out puts a sine wave. This unit is a data center unit, sine wave output, avr boost/drop and excellent surge protection. Give it a try, you'll see how well it works.