Screen - likely nothing you can do about it, since it's a progressive age thing. However if you can find a new screen, it should improve.
Buttons - disassembling and cleaning the remote might help here. Note that you need a #7 Torx screwdriver (#6 also seems to work), and remember that there's a screw under the label on the back.
There's some tips on disassembly here:
[Link: remotecentral.com]