I feel your pain, bro..........................
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Now I didn't go as far as you did but the wife had bought a new Logitech M215 wireless mouse\K330 keyboard combo for her box & was trying to set it up on her computer yesterday evening when I came home from work.
Naturally she was not getting anywhere w/ it & asked me to get it all working for her so she could FB.........................
1st thing I saw was that she had plugged the USB receiver in 1 of the bad USB connectors on front panel of her case (Antec Three Hundred) that I had unplugged some 8-9 months back (she kept bumping into the USB Bluetooth dongle that she had for her Bluetooth earpiece & ended up breaking both connectors) but I didn't say nothing. So I turned her box off as I was going to pull it out to access the rear, disconnect the old wireless receiver & plug the new one in1 of the USB slots on the back. No sooner had I done this & slid it back in & pushed the power button to turn it on I got nothing.............
Looked inside the case & I could see parts of the mobo was still lit up but no start up.................
Pulled it out & opened it up & checked all over & couldn't find nothing wrong so I had assumed that the PSU had failed...even though I could see that power was on the mobo. I wasn't gonna get another 1 from our local Best Buy (this was the 2nd one in this box) so I was gonna wait until the AM to order 1. So when I informed the General House Manager that she was gonna be out of commission for a while let's just say that there were a few words said.......& since I had been working on my box all week (had installed a Plextor M6e 512Gb PCI-E SSD & loaded fresh Win 7 SP1 install & loaded all drivers, apps & games & set all up over the week) the General House Manager thought I should put out a little more effort to fix her box............whew!
Anyway while I was messing around on my box I got the idea that instead of ordering a PSU in the AM that I would check the power switch in the case just to cover all bases............
This morning I pulled the box back out, opened it up then got my company issued Fluke voltmeter out, set it up for continuity & tested the power switch leads when I pushed the button in...............nothing.....
hhhhhmmmmm. Retested & got the same. Just to check something else I checked the reset button leads........meter beeped when I pushed the button in....leads are good & meter working. Retested the power switch leads again.....got nothing. Switch is bad.................now what. Went online on my box to check Antec's site for spare parts as I was going to also replace the bad USB front header block as well......nobody home on the weekend so the wife is still looking to be grounded...................un
til I realized that I could use the reset button as the power button as a stop gap measure until I could get the parts ordered so I plugged the reset button leads on the power switch pins on the mobo, put it back together & hooked all back up, hit the button & volia! Her box powered up w/o issue. Went into the UEFI using her old keyboard (new 1 wasn't working yet) to check for initialization & saw that both mice & keyboards were initialized but the new board wasn't working....? Checked the batteries in the new keyboard & found them installed backwards....................
....... I didn't say nothing bout this, just put them in correctly then checked for operation....all working OK. Shut down, removed the old receiver from the box (while I had it out of her desk I removed all the extra cabling & power supplies that weren't being used anymore........didn't say nothing bout that either), hooked all back up & booted her box into Windows, went online & downloaded the Logitech Setpoint software for her combo & installed it & set all up. Now after all this was done the General House Manager came thru the door to see her prized possession up & running she was apologetic after that.........................
......
Now you prolly don't have this problem but I typed this to let you know that you ain't by yourself as it's easy to miss stuff that creates similar symptoms so is not a easy find..............& it certainly don't help when you got the Boss yelling at you either............

I hope you got it under control...................
