My son's laptop keyboard (Acer Aspire One running Windows 7) can no longer type E or R using shift-e and shift-r: pressing shift+e or shift+r simply does nothing. I can, however, toggle Caps Lock, then press e or r, and get E and R. The symptom is the same using the "On-screen keyboard" program, leading me to believe that it is a software problem. Rebooting did not fix the issue. The symptom remains the same if I turn Sticky Keys on: pressing Shift, then a key, will let me type e.g. W but not E or R. However, all keys work normally in Safe Mode with Command Prompt.
Googling turned up several similar issues, but they all differ in the details: Either on-screen keyboard does work, or the shift key won't work with any keys at all, or some accessibility option was turned on by accident.
Any help appreciated!