NEED HELP for COMPUTER :(

[komputa4dumies]

Hello everybody...yesterday I built my first computer

AMD k7 1.2ghz 266
Asus a7v133 mobo
384MB Ram
Turtle Beach Montego II
USR 2977 Hardware Modem
DVD-Rom & CD-RW
Antec Full Tower Case with 300 watt PS

It worked last night but today it isn't :|...Could it be the ps? How can I tell which part is not working now? Please help! Thanks a million.

 

[TunaBoo]

What happens when you turn it on?

To tell what part is bad

1) Strip it down to the essentials. Mobo - Power supply - Vid card - CPU - RAM

2) if it doesnt work then, switch those 5 parts 1 by 1 till it does.

 

[whitelight]

to test if it is the psu, unplug the power cord and the atx power connector, take a paper clip and connect the green and any black wire on the atx power connector, and then plug the power cord back into the psu. if the psu turns on, it's fine. (don't touch the paperclip while the psu is plugged in. )

i also have a similar power problem on my comp i'm trying to troubleshoot and what works for me is pulling out the atx power connector and then plugging it back in. my comp will boot up after i do that. i'm still trying to figure out if my psu is to blame or my motherboard, cuz an old psu plugged into my system gives me no problems.

 

[komputa4dumies]

What happens when you turn it on?

When I press the button to turn on the computer, nothing happens...It WAS working last night though!