Knoppix booting: invalid screen mode error

[poolwin2001]

When i am booting Knoppix 2.78 from a CD,It gives the error :Invalid screen mode
0 ff77 80x60
1 ff45 80x45
etc
Enter correct mode number or scan

When I enter 0(or ff77) or any other value,it continues upto showing the wallpaper and then crashes.
Thanks in advance

[ceptimus]

Are you sure it's crashed? Sometimes it just tries to use a higher resolution display (e.g. 1280 x 1024) than your monitor can cope with.

Try pressing Ctrl,Alt,- (i.e. the three keys, Ctrl, Alt and minus key all at once) a few times as this resizes the screen resolution on the fly. The Ctrl,Alt,+ combination goes in the other direction.

[poolwin2001]

I used crashed in the sense that mouse didnt move,CPU didnt show busy,CD drive didnt show busy and i couldnt take out the CD.
I will try what you suggested.