One of the computers in our office began exhibiting curious behavior yesterday afternoon. While the user was in a word document, it would begin inserting ;E? followed by a carriage return, resulting in:
proceeding down the page.
If the active window is not something that can be typed into, then it instead beeps.
There are Occasional variances occurring, %E? also shows up, and occasionally there is no carriage return following the entry. We left notepad open and overnight accumulated 25 pages of the entries.
We have run Malwarebytes, Combofix, RKill, TrendMicro virus scans, but after cleaning what they found, the problem still occurs.
We have also tried different keyboard and mouse combinations, and different USB ports to plug them into, but the input appears even with no user interface devices connected. Swapping the original devices to another pc did not cause the issue to appear on the second pc.
Has anyone run into an issue like this before? My search fu hasn't turned anything up, but that particular character string usually just brings up results of the letter E.