A Corsair CX500 watt should be enough, I'd go for the CX600 just for the eatra watts, though.
If you've already used the 330 watt PSU, you mave have already done damage to the rig if you are having problems, you won't really know for sure until you acquire a better PSU.
You shouldn't have more than 200 watts excess power on the 12v rail past the maximum, it could affect the capacitors. So if your total 12v rail for all hardware (ram, hdd's video card, network card, sound card external ports etc) is about 400 watts then that would calculate to about a 500 watt PSU. The only reason I'd go for the 600 watt PSU is for any excessive peaks or spikes that may occur and that there is a fair amount of excess available.
330 watts would be about 250 watts on the 12v rail, the cpu/motherboard would use about (I haven't looked, just a guess) 100 watts, the video card about 100 watts, everything else about 100 watts so a total of about 300 watts, 50 watts more than you've got with the 330 watt (total power) PSU. You'd need to check the spec sheet for each piece of hardware as to what the actual watts required would be, to be certain of the actual requirement but the CX500 would be good enough for you.
hi I was just in a chat with a dell member and they confirmed that the system could not handle more than 330 watts. Have you tested 600 watts or 500 watts to test it actually works? Here is the question and response from the dell helpline thingy ma jiggy.
Do you know if it would be possible to switch it to a different adapter like a 500 watts one MARIA A
No it is not possible. the desktop can only handle up to 330 watt