This is my first attempted at anything Linux based after deciding not to go with WHS for a home server.
I installed from a DVD fine and got to the stage of evening setting myself up an Admin account but as soon as I log in my screen goes all scrambled and I am unable to read anything, mouse moves but can't do anything else since I cannot see what I am looking at

The system appears to still be active since power management turns off power to screen after a period and maybe even activates a screen saver.
I am running on a AMD Athlon X2, 4GB DDR2 RAM, the Motherboard is a ASUS M2A-VM which has an integrated ATI Radeon X1250 graphics chip and I installed on a new 320GB SATA HDD, with two additional drives for data only.
Any help on what to do from here would be much appreciated, I have attached an image so you can see what happens after I log in.
Edit: I am able to ping the machine and get a reply from it.