Not booting up after HDD install
hey guys so I made a horrific mistake somewhere by attempting to add a HD on my iMac.. I had ordered the wrong SATA power cable and so put the machine back together , and only left out the optical drive out, which has never really worked properly since I got it.. Anyway put the thing back together and now I've got nothing. No screen, no chime, nothing. Just fans spinning very loudly, and LED lights 1 and 2 lit on the motherboard. Strange thing is I had messed up the data cable for the LCD , which is extremely fragile :( but when plugging back in the smallest wire for the LCD all power shuts off and the two LED goes off as if there is NO power at all.. So I tried my second monitorn - my tv with the mini display to HDMI and nothing either..
I'm really at my wits end with this.. I consider myself to be quite handy with electronics, I've built computers and laptops from scratch and considered this tone a straight forward affair... How wrong I was.. So my iMac is sitting no screen, just the 2 LEDs lighting up and a very loud fan..
Any help or assistance on what has happened would be greatly appreciated ...
Many thanks
Update (01/01/2016)
Tried the suggestions to no luck... Fans still spinning wildly, no display, still only two LEDs on... One thing I've just noticed, when the iMacs not powered on, there is a strange clicking noise and buzz from the power supply... Could this have been shortaged during the HDD replacement?
Also when reseating the ram I turned it on before putting them back in and I got a few beeps .. Guess that's the logic board telling me there's no ram.. And hoping by that nothing is wrong with the logic board... Argh I wished I never even bothered now!