USB Mouse sometimes not recognized at startup

Over the past three weeks or so, there have been probably seven times my wireless USB Nexus Silent Mouse has not been recognized on cold computer startups (usually morning). Windows 8 (Pro x64) throws up a message that a USB device wasn't recognized, and I don't see a mouse cursor. Unplugging and replugging the USB mouse's stick, which is in a port on the front of the computer, solves it. The mouse driver is up to date, changing USB ports hasn't made a difference and the batteries are fine (and have been changed). Where else should I look to figure out what's going on? Thanks,

Check in the device manger for mouse and other pointing devices,properites, then under power management, that it's unchecked for power saving.

There are only two choices and what's checked is "Allow this device to wake up the computer." Is that what you mean? Thinking back, this may have started soon after updating from Win 8 to 8.1. Might the install have changed the setting? I don't use sleep mode often, but when I do it's the keyboard not the mouse for wakeup.

I wonder if something else that's happened twice in the past few days is related: My monitor setting in Power Mgt is to go into sleep mode after 20 minutes (screensaver off). Upon return after longer than that, I hit the Esc key to wake everything up. Last night, for example, I came back after a few hours to find the Esc key woke up the SSD, or so it sounded, but the screen remained dark. The obvious question was whether the computer had crashed, but looking at Event Viewer afterward there were a long string of .NET and cryptograhic errors, at least the .NET being unusual, but nothing directly indicating a crash. I shut down manually and on reboot found a bit of data corruption (two browser extensions no longer there). While I had been away, I was running a VPN connection and Vuze. The previous time this happened a couple of resident apps had lost their config settings (Mailwasher Pro and Bookmark Buddy). It's easy enough to disable screen turnoff in power management (never), but I wonder why the screen setting would have anything to do with it. It also occurred a couple of times a month or two ago, but then had been find until this week. Could this also be a power mgt issue?

For my desktop I never use sleep/hibernate mode....and the general consensus is that it's broke under windows 8/8.1. Even I've experienced it not working under both 8/8.1....so I don't bother with it. However, I do let my monitors go to sleep.

To be clear, sleep/hibernate is not an issue here. This is simply walking away from the computer, monitor goes to sleep after awhile, and then coming back later and not being able to get the monitor image back, whatever is causing it. Is there a definitive way after rebooting to tell if the computer crashed and why? That might help advance things.