Basically, if i press the full stop key, it will type between one and three extra full stops per keystoke. Ever weirder, if i hold shift and press the key, it will continue to produce'>' cxharacters so long as shift is held down.
At the moment, i've dropped the systems 'repeat delay' option down a notch, which stops it producing extra full stops on the initial keypress, however, now, if i press they key more than once in quick sucession, it will prduce the first full stop, pause for a moment, and then produce a randum number of additional full stops.
I've already blasted the keyboard with compressed air about four times, and disassembled it to check for debris (There was none). At the moment, my only fix was changing the repeat delay, which seems to only stop the random initial typing, and doesn't stop the system producing more than i type when pressing the key quickly.
The full stop key is the only one affected by this (i've checked all the other keys already).
The keyboard itself is a Logitech MX3200 wireless keyboard.
The system is custom-built (By yours truly). It's a Core 2 Duo 2.4GHz, 2Gb RAM, 250Gb HDD running Vista Premium x64. The problem has never happened before on this computer, and i don't have any other computers available for cross-system testing.