You can not. But if you are saying that you have sorted out the problem or for some other reason want to delete this question I can do that for you.

Please confirm by posting back or by sending me a private message.

I noticed I have an old FF (17.01), though I have 2 PCs, both autoupdate, and the other PC properly has FF21. They also sync history with each other even though Sync is turned off and I don't even have a Sync account. Lots of weird stuff's goin on.

Are you using a wireless keyboard?