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I have a problem with a PC where the power sometimes acts up on boot. This PC has a mouse with back-lighting. The back-lighting on the mouse will 'sometimes' flicker and the PC will not accept any input from the mouse. When this happens the USB keyboard will also boot with troubles. Rather than flickering (it has back-lighting too) it will simply not power (No input here either.) Now, this sounds like a motherboard issue, except for one thing I am hoping somebody can explain:

If I disconnect the devices and reconnect them everything starts working again. No restart is required or anything of the sort. What might be the problem and is there a fix short of a new motherboard?


Some new information: It seems that the mouse is where everything is going wrong. I have reinstalled motherboard drivers, disabled superfetch, and disabled readyboot. None of this has helped the issue. I have determined however that it seems to start the trouble with the mouse. If I unplug the mouse and plug it back in, everything goes back on track (the keyboard begins to work.)

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First of all, try the devices on another computer if possible. Second, consider checking things besides the motherboard like the power supply. Third, reconnecting would reinitialize the devices and thus fix an incorrect initialization. Device LEDs lighting up is usually normal upon boot, does your lighting-up differ from that? – Tom Wijsman Feb 12 '12 at 0:24
Maybe I should clarify, when I say boot, I mean at the windows start screen. – Serodis Feb 12 '12 at 1:32
@Serodis Which OS? Does it ever fix itself in time? (max time I would possibly give it 3-5min) . Did this happen when you first installed? – Psycogeek Feb 12 '12 at 4:06
This didn't happen at first, it is Windows Vista and the items work fine on other computers. It also seems that it only starts flashing once Windows starts. This happens BEFORE login. – Serodis Feb 12 '12 at 17:08
@Serodis the reason I ask is because on my own system, the faster the readyboot stuff attempts to make my boot, the more thrashing and out of order, and collisions it creates, for me it is mostly after log-in, but I autolog locally. I am wondering for myself if i should toss this "feature" or clear it, my boot is not slow, to be needing it. Enumerating 50 drivers at a time, while running 10 pieces of software, with 89 services starting :-) Then with the overprotection of a stalled item. – Psycogeek Feb 13 '12 at 0:47
up vote 2 down vote accepted

Check "devices by connection" in device manager - maybe mouse is oversubscribing power on USB hub shared with e.g builtin webcam and pluging it into other USB port easily solves the problem

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Going to do some testing this weekend, I will come back to the question. – Serodis Feb 15 '12 at 23:07
Looks like I may have found the problem. The computer in question has a keyboard with a built-in low-power USB hub. This hub seems to have been failing on boot. I am going to test this to be sure, but it seems the most likely. Oddly, when checking devices by connection, however, it lists it as a sibling rather than a child and I wasn't aware the PC had been setup in such a way. I will come back after further testing to accept if it no longer fails. – Serodis Feb 18 '12 at 0:06
Yes - each thing connected draws power from USB. If that hub was parent it would just add a bit of latency to say USB hadphone – ZaB Feb 18 '12 at 2:18

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