Strange problem just started on a Windows 7 Ultimate laptop.
Create a new document and start typing - all goes well and response is good. Characters can be typed quickly and appear immediately.
Try to delete characters in either direction using Backspace or Delete and the character deletes right away but it then takes 2 seconds before another character can be deleted. Highlighting multiple characters is ok - deletes as normal but again 2 second delay before delete works.
Word and Notepad both show these symptoms.
No new software or fonts added recently.
Nothing appears in any event logs.
AV is AVG and that doesn't show any issues.