No POST/display after cleaning my PC

[Darklurker]

So my HDD appears to have died. When I went to remove it I noticed that it was time to give my system a nice routine cleaning, with air/alcohol/contact cleaner, as well as reapplying thermal paste. After reassembling it, the system just won't boot. It "powers up" (fans and mb lights), but there's no display or beeping of any kind. It doesn't shutdown by itself either.
I followed many tips without any success. Using only one RAM stick changes nothing. Using no RAM at all does produce the expected beeping, though. I've also tried resetting the CMOS. I checked all connections and tried setting my components again with more care, but nothing happened. I don't have any spare components available for testing. Any ideas?

My system (a couple years old on average):
-Asus Z87-Plus
-i5 4670k, OCed to 4.2GHz
-G.Skill Ripjaws 2x 4Gb 1866Hz
-Gigabyte gtx760 (Windforce)
-2 SSDs, Samsung 840EVO and 850EVO
-Corsair TX650

[Butler to Baby Sloths]

If you have no storage device plugged in, does it give you a "no boot drive available" type of error?
If you don't have the graphics card plugged in, do you get a video signal if you use onboard graphics?

[Evildeffy]

Did you possibly forget to re-plug the EPS connectors back in (CPU 4 or 8 pin)?

Seen this happen much more times than people care to admit.

[Butler to Baby Sloths]

Did you possibly forget to re-plug the EPS connectors back in (CPU 4 or 8 pin)?

Seen this happen much more times than people care to admit.

Mmh, especially as it is the one plug that is super-difficult to reach if you have an air cooler.

[Lathais]

Did you possibly forget to re-plug the EPS connectors back in (CPU 4 or 8 pin)?

Seen this happen much more times than people care to admit.

I was guilty of this once. Was really really confused and getting frustrated so I just "gave up" for the day. Next day when I was looking at it again i felt like a complete idiot. Have seen it be the problem with friends PCs a few times as well. Also, willing to bet at least a few times here on these forums when this answer is given and the OP never shows back up, it's probably what happened.

- - - Updated - - -

Mmh, especially as it is the one plug that is super-difficult to reach if you have an air cooler.

Yup, exactly what happened to me. Actually had to take cooler off, clean paste, attach cable, re-apply paste and heatsink. Was a pain and made me feel like a noob.

[Darklurker]

If you have no storage device plugged in, does it give you a "no boot drive available" type of error?
If you don't have the graphics card plugged in, do you get a video signal if you use onboard graphics?

No and no.

Did you possibly forget to re-plug the EPS connectors back in (CPU 4 or 8 pin)?

Seen this happen much more times than people care to admit.

I didn't. I wish it were that simple.

[Evildeffy]

No and no.

I didn't. I wish it were that simple.

The only thing I can think of is that you possibly overtightened the CPU heatsink.
Remove the Heatsink and the CPU itself, inspect the LGA contact pins if none are bent or something.
Then inspect the bottom side of the CPU .. check for dirt, scorchmarks etc.

If not then try to put the CPU back in and the re-attach the cooler with a new coat of paste.

Do that and let's see how far it goes.

If you suspect anything weird with the contact pins or CPU when you see it but aren't sure then make a picture of both and link it to us here.

[Darklurker]

The only thing I can think of is that you possibly overtightened the CPU heatsink.
Remove the Heatsink and the CPU itself, inspect the LGA contact pins if none are bent or something.
Then inspect the bottom side of the CPU .. check for dirt, scorchmarks etc.

If not then try to put the CPU back in and the re-attach the cooler with a new coat of paste.

Do that and let's see how far it goes.

If you suspect anything weird with the contact pins or CPU when you see it but aren't sure then make a picture of both and link it to us here.

I'd french kiss you now if I could. I checked my CPU and the socket, both looked pristine. So I tried to place my heatsink (a 212 EVO, I hate putting that thing on) with less tightness and it did work. Thanks a lot for the help, guys.

[Evildeffy]

I'd french kiss you now if I could. I checked my CPU and the socket, both looked pristine. So I tried to place my heatsink (a 212 EVO, I hate putting that thing on) with less tightness and it did work. Thanks a lot for the help, guys.

You're welcome.

If all is working now you can tighten the screws to their set amount now, it should work so they don't need to be a bit less tight as you have it now.
Seen this happen a few times where people think they put the 212 EVO properly but the CPU bracket is not in the hole in the center but ontop of the side.

This caused it, now you've probably set it right in the center and it works, thus you can properly tighten the screws again.

Edit:
Also if you'd kiss me you'd better be a good looking woman or I'd probably murder you.

[Deleted]

snip snip snip!1!1

Edit:
Also if you'd kiss me you'd better be a good looking woman or I'd probably murder you.

Unless you bought him dinner first

just kidding