Similar problem with my Dad's old VCR: plays pre-recorded videos fine, but anything recorded from TV just doesn't work: it's down to the tuner (RF-converter?)part of the VCR having gone wrong: check what picture you're getting when you try to start recording on the video channel: if you're not getting a clear picture the video will just record what it sees too. (And it's not just fuzzy needing tape heads clean, it's no pic at all, random snowy stuff!) I tried to re-tune to the video channel but that didn't work either.
So, I gave Dad OUR VCR, and went and bought ourselves a Panasonic combi box: it is VCR player/recorder, DVD player/recorder, AND digital TV receiver all in one. Not the cheapest, but does a great job: we had a lot of treasured videos of the kids which we can now convert to DVD before VCRs become obsolete. (I bought a cheaper brand first but had to take it back as it kept "locking up", and the recording quality was very poor). The Panasonic also allows you to "time-slip" if you get interrupted while watching a programme. You can only record from digital TV the channel it is set to at the time, but as long as we still have analogue TV, you could be watching in analoge while recording digital.