[SOLVED] Swapped out air cooler, now computer will not POST. (SOLVED)

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Dec 20, 2012
[UPDATE: After completely rebuilding the system, I turned things on and after 5 attempts, it finally booted in Windows. :unsure: I think the machine is just possessed.]

Greetings everyone -

I have a self-built system that I've been using since Dec 2019. For some reason, every time I open the thing up and swap something it will no longer post afterwards. It'll turn on for 27-28s then power cycle again. Every other time this has happened I've simply re-seated the RAM and GPU and the problem will sort itself out after one or two attempts. After installing a Hyper 212 EVO today, I simply can't get it to POST, let alone boot.

I have reseated the GPU and RAM three times, testing each stick separately and in each channel pairing. PSU is powering up all the fans (including GPU) and the keyboard/mouse. Monitor is giving me a "No Signal" message, which is typical when this has happened in the past.

I did re-seat the cooler once, giving it and the CPU a thorough cleaning per usual. CPU pins are clean and straight.


  • Asrock B450M/AC
  • Ryzen 7 3700X
  • MSI RTX 2070 Super Ventus OC
  • G. SKILL 32GB (2x16GB) Ripjaw (F4-3200C16D-32GVK)
  • Intel 660p M.2 2280 2TB
  • Seasonic FOCUS 650W 80+ Gold
  • Win10 64-bit
I am certainly not claiming to be an expert, hence my presence here, but I've been building PCs for 25 years and I've never had a build where it has this failure to POST issue after every hardware change (or even when I simply take stuff out to dust). At this point, I think I'm going to take everything out with the case and treat it as a new build, even though NOTHING about the system has changed since I last booted successfully. Just today's shenanigans with the new cooler.

I'm checking in here just for some insight from you veterans on what you may think the problem could be. Maybe I've overlooked something (I have read the POST sticky), though I'm scratching my head as to what. Hopefully I didn't bonehead-it-up and damage something, but that would be a first.

Thanks for your help in this.

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