I hope I can ask a DVR question here

[mr_lebowski]

3. Besides Aspect another possibility is that the DVR supports resolutions larger than your TV

Such as if you had a 4K-capable DVR with a 1080p TV, and the DVR was set to output 4K. Or your TV got set to 720p mode while the DVR is still outputting 1080p.

These are less likely, but conceivable scenarios ... an issue with Aspect is more likely ... you may have a zoom mode enable on the TV. A clue to this would be whether other sources appear cut off as well (like a cable box or dvd player or whatnot ... if the TV aspect was zoomed, it would likely be for all sources ... though not all TV's are like that).

Edit: look for buttons on TV remote labeled Zoom, Picture, Aspect, or a screen icon w/arrows pointing outwards away from the screen. Or check menus ... normally it's on the remote. Note this is PROBABLY on the TV remote i.e. the one that came w/the TV ... but could be adjusted on another one if you programmed other remotes with the code to operate your TV directly. TV remote is your best bet to fix it even if it didn't cause it to begin with.