That is a weird one for the following two reasosns:

1. If recordings look good on your PC then it rules out everything from the video input to the hard disk.

2. If menus are fine then this rules out everything from the hard disk to the video output as the background animations in the menus are purely recordings on the hard disk too.

Statement 1 and 2 use different circuitry inside the TiVo and covers pretty much everything on the board.

If you had said that menus also looked wrong then I could say it is a fault in the playback circuitry given you mention that downloading recordings to PC look OK. But menus look OK so unfortunately from a hardware technical point of view I'm stumped. It *may* be some obscure fault in the MPEG decoder chip but if it is I've never seen this behaviour before. Usually it can be narrowed down to either a definite recording or a definite playback circuit issue.