New
#11
Toggle Keys mystery solved! It was the sound card .....
I had Soundblaster xfi extreme sound card installed and found that there were persistent problems with media player playing music, which slowed then speeded up when I did anything on the PC, there were odd buzzes, crackles and pops, and all that despite having the latest drivers installed which were so say compatible with Windows 7.
The card has now been removed and I'm using the on-board sound with a special plug to accommodate my speaker system and everything is working as it should, including the Toggle Keys beep.