^ question , the reason i say without opening case is because i opened it and theres no indication on the psu whatsoever so i need to figure it out another way, Please help me!
Well, if you are unwilling to remove the PSU and check the sticker, perhaps there is one other way.
Place both hands on the PC, close your eyes and concentrate really, really hard. If you are lucky you can perform the Vulcan Mind Meld like Mr. Spock and telepathically find out how many watts the PSU will provide.
ZOMG, i tried it i was off by .5 watts
i tried that on my old HP Vectra. it was 185.5w, danm off by .5