I just bought a new dell a few months ago, an inspiron 351.
It has been working great but lately the keyboard has been not responding if I ever restart or turn my computer off then back on.
The only way I can fix it is to unplug it from it's current USB port and plug it in one it hasn't used yet. This has worked for awhile, but I woke up with morning to my computer restarted (must have been some updates automatically restarting my computer) and my keyboard did not work on any USB ports in the back, so now I have resorted to using the front USB ports.
Pretty soon I will have no plugs for my keyboard, but all my other things work just fine in the USB ports.
Sounds like you may have a mess developing under the hood. Take a look at your Device Manager and see if you have a lot of yellowed-out ports and other odd-looking stuff.
I wouldn't let updates or anything else automatically restart my computer, BTW. That sounds like asking for trouble.