outpost31

Same result after adding a GPU.

Almost! I'd just need to buy more memory and another case.

I do have a 1660 that I bought for this that I haven't used yet, but I'm thinking that won't cause the system to reboot immediately. I'll try it, though!

I don't even get to the point where I can choose a boot device, unfortunately.

These are great suggestions! Unfortunately, I'm using an onboard msata drive, so there aren't cables. I did try connecting a sata drive and it didn't seem to make any difference. I can't get into the BIOS to make any changes. At most, it'll start to load the bios splash screen.

I checked both boards for any swollen caps. One board was new in a sealed box, the other more recent one was a "working pull".

The Kraken is new out-of-the-box. And I don't POST long enough for temps to rise from what I can tell.

Yes, I've tried both a UPS and wall power. Also, another power cord.

This new HTPC build powers off 95% of the time prior to POST (within 3 seconds), 5% it starts to load the BIOS screen but stops midway (always at 19 seconds). The fans spin during this time. I've been troubleshooting on and off for a month and 3 or 4 times was able to get the system running long enough to install Windows (thought the issue was fixed!). But then once I powered the system off the no-POST issue has returned. Here's what I've done to try to resolve this: Checked all connections, including reseating memory Pulled, and alternated one of the two sticks of memory Pulled working memory from another machine. Verified memory was placed in correct slots for Dual Channel config (tried memory in all possible slots) Replaced the PSU with new one (with the one listed in the build), prior was a known-good. Pulled mobo from case and attempt to boot while on a static bag and cardboard box to check case short (no change) Both ATX12V and ATX are connected Replaced the motherboard (with same exact model) with new one. Verified mobo is at latest bios revision (f11) Added a PC speaker (I will only get a single beep on successful POST, all other times it does not beep, and will still shutdown) Removed all devices except one stick of memory, and CPU (no change in behavior) Verified memory used, CPU, and mobo firmware are compatible on Gigabyte's site. On the rare instance when the system does boot and stay running, I loaded cam to monitor heat. All temps during that time were what I'd expect from a liquid cooled system 32-37C Swapped which mobo fans were powering which fans (this got it to boot, once) Cleared CMOS via jumper (this got it to boot once, but not consistently) Replaced CMOS battery with new one. Monitored temperatures with infrared heat gun (typical result) Added a spinning drive to so where was a minimum load on the system and removed msata drive Tried a different PS switch in case the case one was defective (no change in behavior) Tried removing all front panel connectors and jumping PS header with a screwdriver. Removed SSD and HDD in attempt to just boot to BIOS (no change) Removed all memory and the system will start POST and beep continuously and then turn off. Replaced CPU with a NEW i7-3770 CPU Parts list: CPU Intel - Core i7-3770 3.4 GHz Quad-Core Processor CPU Cooler NZXT - Kraken M22 Liquid CPU Cooler Motherboard Gigabyte - GA-H77-DS3H ATX LGA1155 Motherboard - Memory G.Skill - Ares Series 16 GB (4 x 4 GB) DDR3-1333 Memory Storage Kingston - 120 GB mSATA Solid State Drive Power Supply Corsair - SF 600 W 80+ Gold Certified Fully Modular SFX Power Supply SilverStone Grandia GD09B ATX Mini-Tower Computer Case Enermax UCTB8 T.B. Silence Twister Bearing 80mm Case Fan (2) Enermax UCTB8 T.B. Silence Twister Bearing 120mm Case Fan Note: using IGPU I'm way over budget (especially for parts of this age), but I'm determined. I've pretty much replaced everything on this build at this point and am still having the same issue. Can anyone save my mind here? Solve my problem and I'll reward you with a game off steam or something equivalent!