I am not having success booting from Knoppix on my Compaq Presario, with a Viewsonic G773 monitor.

I insert the CD-ROM and boot, and the drive spins for a while, sounds like it's doing work. But nothing ever appears on my monitor screen. I have a feeling the computer is booted, but the monitor simply isn't displaying anything, since when I hit space the CD-ROM spins some more.

I am having the same problem with every other Linux distro I've tried, including Red Hat, Mandrake, and Suse. This is puzzling to me since I already have Mandrake installed on the machine, and it works fine when I boot from the hard drive. (I'm trying to load from Knoppix b/c I did the Mandrake install over a year ago and forgot the root password).

Any ideas?

Thanks!