PS2 Going Mad

[Geo147]

I have just started playing Medal of Honor: Frontline cdr backup, after about 20 mins of gameplay or if I try to watch the films the laser begins to make all kinds of noises, like it was skiping from 1 part of the disc to another. This problem will not go away if I just reset the console, I have to load up a dvd film and then it will stop. This is very worrying as it sounds like gears grinding when I have reset it and it tries to read the disc.
I have a pal v5 with a neo4r.
Has ne 1 had this problem or does ne 1 know whats going on? Ne help appreciated.