A month or so ago, I was trying to plug in a headset jack. Missed the plug and hit the USB port instead. Saw a little spark, and the system immediately shut down. Was able to bring it back to life with no apparent problems.
Yesterday, the external hard drive (USB) apparently conked out. The scheduled back up failed. The system would no longer recognize the drive. Tried it on some other computers and it still didn't work.
The external drive problem had a funny effect on the main computer. When it was plugged in (even tho not working), the computer slowed to a crawl. Could see the HD working continuously. Took maybe 2 or 3 minutes for each command to execute.
Unplugged the HD, and no more slow computer. I'm replacing the Ext HD.
Now I notice the USB network adapter conking out periodically. This also freezes the computer (as with the Ext HD). On one occasion, pulled the adapter from the USB and plugged into another port. The system reinstalled the adapter and resumed function. However, on another try (after the adapter died), moving to a different port didn't help. But restarting worked.
Have tried reinstalling the USB devices. No help. Tried system restore, thinking maybe a software issue, but now it tells me I can't restore.
The darned thing is working at the moment, but I suspect not for long. Wondering about that little spark I saw.