I have an ASPIRE F5-573G. Ever since I first got the machine, I've had some problems with a couple keys, Num Lock in particular. It seems like periodically Num Lock will just turn off. It seems like it happens more often after I come back after a period of inactivity, or if I go into a remote desktop session, or if the computer is returning from "sleep" (might be related to being inactive). I haven't identified a specific trigger... it seems like it can happen whenever but is more common after these aformentioned events. I don't see the screen indicator that normally comes on to tell me that Num Lock has been toggled when num lock turns off, it just seems to happen silently. I can see the indicator when I turn it back on manually.
The only semi-related topic I found involved changing an "initial keyboard indicators" registery key to 2, but that doesn't appear to have changed anything.
On a separate but perhaps related note, I also have an issue with "insert" being activated randomly, althuogh I don't think it happens as as often. Given that I have to press both the "Fn" and "Del" key in order to activate "insert", I don't think I'm hitting it accidentally.