Black screen trying to run Ubuntu 10.10 Live CD

I'm trying to test drive Ubuntu 10.10 from a Live CD - when I boot from the CD I don't see a menu, the first screen I see is the try/install dialogue box. If I select "Try Ubuntu" the screen goes black (although I do see a white cursor) on the screen. I'm using the 32-bit version of Ubuntu on my system (AMD Athlon 64 3200+ processor, 2.5GB of memory, ATI Radeon 1650 videocard with 512MB of ram)

I did try holding down the "F6" key during the boot (I had noted that it had been suggested that I enter the "nomodeset single" parameter but since I don't get the menu screen I don't know where to enter this..) Even stranger, the system booted up correctly (I got into Ubuntu) without me entering anything after I held down the F6 key several times.

I do not have the same problem booting into Kubuntu - it goes into the menu screen, and then when I select try Kubuntu, it runs without any issue. The desktop appears and I'm able to run the program without any issue.

My system had no problem booting from earlier Ubuntu Live CDs prior to version 10.04 and it appears that 10.10 continues the problem. Any suggestions?

Thanks.