One user has a workstation on which the CAPS LOCK key intermittently reverses function. When reversed, with caps lock off all typing is in caps and with caps lock on typing is normal. This has happened without notice while typing an email message in Outlook and I'm pretty sure while working in Word and Excel.
This started happening a few weeks ago and it happens anywhere from daily to weekly. It may have started around the time of a large Windows update (about 60 updates) although I can't be certain. None of those updates clearly have anything to do with the keyboard or USB interface but who can be sure...
Rebooting the PC restores normal operation. So does disconnecting and reconnecting the USB keyboard.
The user needs the caps lock function so I can't just disable caps lock.
Details follow including what I've already tried.
Dell Precision Workstation T3600
Windows 7 Ultimate SP1
Office 2010 SP2
Dell USB keyboard
All remote access to the PC is disabled.
Kaspersky Internet Security reports no problems.
Ensured that all accessibility features including sticky keys are disabled.
Uninstalled keyboard driver and let Windows reinstall it.
Updated workstation BIOS and USB 3.0 drivers. (And the Intel chipset and Intel memory manager drivers although these seem unrelated to the problem.)
Another Dell keyboard to see if it the keyboard itself. As I write this, the new keyboard has only been in use a few hours.
Any further suggestions welcomed!