So I have theis Gentoo Live x64 bit edition. It goes throught the setup to run the live cd. Nothing fails on bootup, and the input it selects for my monitor are all supported by my monitor. Yet, when I boot it up and Linux is supposed to be running, it just shows an Input not supported, but sometimes it will flicker and display it properly for a few seconds. The video card I am using is an ATI X1650 Pro. I would appreciate any and all help. thanks!!!

Most likely it isn't detecting your display properly, and is likely feeding it incorrect refresh/resolution information. I would suggest using a different LiveCD, like Knoppix, and seeing how that fares.

I have tried to use Knoppix, Gentoo, Mandrake, and Suse to install/ use linux on my pc, and to no avail. I think it is the fact that the monitor is LCD, because it works fine on my CRT monitor.

Are you using the VGA or HDMI input on your LCD? Your LCD might be reporting configuration data incorrectly, in which case you will have to manually specify what settings your LCD can use. The manual that came with it or the manufacturers web site will have a datasheet that can specify the proper resolution and refresh settings... and you will need to tell the LiveCD to use those settings.

I was using the DVI cable to connect from the monitor to the computer, should I be using the VGA cable instead? Ill try that and see what happens, once I find a cable that is lol

Yeh I'd use the VGA at least initially. I don't exactly know the details, but I think the VGA polls the monitor differently than VGA. I know when I was trying to get Linux on a PowerMac G3 with a 19" Dell LCD I couldn't get it to work with DVI, but if I used VGA I could. After you get it working in VGA you can mess more with the settings inside a GUI if you are not quite as adventureous as most Gentoo users.

Let us know how it goes. I used to have issues with displays working properly all the time in Linux, but that was primarily with XFree86 and not X.org. Since xorg, the autodetection for displays has been much better.

And just to check, are you using the latest 2008.x LiveCD for Gentoo?