Input devices (mouse and Keyboard) not working on Inspiron Desktop

I have a three year old inspron desktop running updated windows 8  Suddenly NONE of the input devices are working.  I've tried several different wireless mice, and I've tried both a wired and wireless keyboard.  NOTHING.  I've tried unhooking all, rebooting, then hooking them back up... still nothing.  Tried rebooting with them installed.  Tried switching USB ports.  ARRRGGGHHH.  Since I have no keyboard I can't do safe start (don't even know if that works with windows8 ).

I do have a "repair disk" that I created when the compter was new.... tried rebooting with it in the drive.... didn't do anything other than restart the computer with the same non-functioning input devices.  

I hear my external harddrive working... so it must be doing something... so I guess its not all USB devices that are down.

I did install new logitech software last week, but it worked fine for several days, just quit working when it woke from sleep.  I'd love to uninstall it, or do a system restore, but I can't do that since the mouse is not working.  

Any suggestions/help would be greatly appreciated.

Thanks.