hello, I have a asus maximus v formula, and a bequiet dark power pro 1000w PSU, The thing is that lately it wont turn on, if i press the "start" button maybe it will turn on seconds later or minutes... but today the problem was persistent I couldnt turn it on no matter what.... after alot of tries I figured if I JIGGLE the PSUs on/off switch i can get it to start no problem... and then it will run for days or longer as long as i dont turn it off... So is it the MOBO or PSU problem??? I cant tell and none of them looks faulty and works if you get it to turn on... Please help
Welcome to the forum! Do you happen to have a spare power supply? I think that's the easiest way to confirm if this is an issue with the power supply or the motherboard. If you don't have a spare power supply you can also use the paperclip trick to test the power supply outside of your case.
Of course since there isn't really any load when you're turning on the powersupply through the paperclip trick, however a power supply that has 5V standby issues may have similar issue as what you described. So try using turning the power supply on/off a few times using the paperclip to see if the power supply can power on everytime. If after a few tries and it doesn't power on anymore then it's likely a defective power supply.
If you own a multimeter, then it would be even easier to check the voltages through the multimeter to see if your power supply is working normally.
Also try removing all your RAM and leave just one stick (test one stick at a time), it could possibly be defective memory that's preventing your system from tuning on and nothing to do with your motherboard or PSU.