Page 1 of WHARFEDALE 750 NOT PLAYING SWORDFISH+MUMMY RETURNS DISC 2!!!! ANY HELP???

Both load in o.k and go to menu screen but once i request to play returns to original blue screen. A mate has the same player ( not sure if a later gen. than mine and both the discs play fine).Can`t be a disc fault cos they work on same machine. Is this a error with my machine or is anybody else having the same problems with these discs. I have about 30 films and all others are o.k!!
Read a forum message with similar problems and recommended using GOTO button and requesting chapter from there. I will try this when my mate gives me the discs back!!! says Swordfish is excellent. HOW THE HELL WOULD I KNOW TILL I TRY THEM AGAIN!! Does anybody have any other ideas or is this my best bet. THANX if you can help.