Computer won't boot with 3rd HDD installed

[miculelectron]

Hello,
I recently added another HDD to my desktop pc. It successfully boots 1 time out of 5 tries.
When I press the power button, the green led starts up and after 2 seconds the pc shuts down. If I unplug the pc then plug it again to the power source, it works one time or two times, then it refuses to boot again.
If I remove one HDD, leaving only 2 (I have a total of 3) it seems to work fine.

I have to mention that the PSU ocasionally has some problems. But it is 450W and as far as I know a HDD uses abot 10 W. So this shouldn't be a problem, right?

Please, advice me how should I do?
Thank you in advance.

Also, offtopic: why 2 HDDs won't appear immediately in explorer after windows 7 boots , but only after 2 or 3 minutes?

 

[Layback Bear]

Welcome to our forummiculelectron.

The first thing the good folks will need is your (My System Specs) filled in completely. Including your power supply and what security programs you have installed.

Use this tutorial by Brink to get you started.

http://www.sevenforums.com/tutorials/180324-system-info-see-your-system-specs.html

Then this tutorial by Golden done so we can see how things are with your disk installation.

http://www.sevenforums.com/tutorials/274797-disk-management-post-screen-capture-image.html