graphics trouble!!!!! HELP PLEASE

hi i'm new to linux and i downloaded kubuntu, i have placed it on my hard drive so that i have a dual boot system where i can choice which OS to boot for now so that i can get used to the new linux, however i cannot seem to boot kubuntu properly i can start it and get the loading bar but then once it has finished it says it is not in the right video mode and underneath says ( optimum video 1280 * 1024 60hz) i have checked on my windows boot and my resolution is already in 1280 * 1024 so i do not know how to get around this problem. I have a Nvidea Gforce 6800 graphics card 200gb of hard drive, 3.2Ghz processor and 2 Gb of RAM. Please help and explain well because i am new to linux so cannot understand if extremely complicated and could you please advise whether kubuntu is a good place to start or would linuxmint be better? thank you in advance! Vbkid57