Hello i have a problem it started about 2 day's ago . When i tried to power my PC for the first time i had to push power button until  my pc started working (sounds were like an OLD engine is STARTING) The next day it wouldn't START and i had to take cmos battery and put it on again and once again pc powered on but like an old engine. So my question of the day is: would replacing cmos battery solve my problem or only replacing power supply will work magic on my machine? (I know there are similar problems but never found anywhere the same problem as i had either people had problems with cmos or pc turing on like and old engine.I personally dont see how replacing the battery would help you in any way. When your Computer is loud (like constantly, not the stuttering sound of a harddrive that is under high workload), its usually the fans doing it. So maybe chek the settings for those if you can (catalyst control center or nvidia thingy)I know it wouldn't help just to confirm my theory . And not loud i mean it starts like an engine that is failing i mean you push it and it try's to start the engine i have to hold power on button for 5 - 6 secs for it to start and in those seconds he makes a sound that he tries to start but actually can't do it  and only after those 5 seconds he finally powers on when i shut down my pc i have to remove and place back my cmos battery in order to start and the process just keeps rotating . (When i shut it down and try to turn it on again it completely ignores the power button and is practically dead the only thing that helps me right know is removing and putting cmos battery again and again)Did you build this PC ? ?
You might want to check that the front panel header connectors are correct...power/re-set/hddLED etc.

P.S. The CMOS battery wouldn't cause this condition but i would replace it anyways...No i didn't build it + a person who built it made it like 3-4 years ago and this problem appeared only now  my theory is that my power supply might be dying but i don't know for sure because i find it very strange that making this trick with battery actually fixes it for a period of 1 pc session so i wan't to clear things out . Also i have a theory that my pc doesn't have enough power to start yet it has enough power to sustain session but i find it very strange that i need to hold "power button" for few seconds for it to power on and meanwhile i'm holding power button i hear like it's trying to start (sound is like when you're trying to start your engine without LUCK) and then after few seconds of those sounds it finally decides to turn on. Step 1) Replace CMOS battery...Part# CR2032...available anywhere.

Step 2) BORROW a known good PSU from a friend of the same or greater wattage and swap it in there overnite...you'll know by morning.