How can I delete corrupt recordings on my Thomson Digital TV Recorder 250GB?

I have several recordings now saved on my hardisk and they have some how become corrupted.

Sometimes the recorder deletes them automatically but in some cases, they remain. When I go to them, the box becomes stuck and freezes. I am unable to carry out any functions (include delete). The box eventually switches itself off. Otherwise, it works as normal and continues to record, etc.

Any answers on what I can do to delete them?