I have a serious problem with my copy of Ubuntu. I had Debian 7.1, and had no idea about how to install Ubuntu. I tried with tutorials off of other sites, but every time I log in Ubuntu, it completely freezes, and my screen shows some sort of lines made up diagonally, leaving it unusable.
I installed Ubuntu 13.04 in the exact same partition as Debian 7.1 (erasing it) with 168GB. I made the entire install correctly, no problems. But I had this problem even when I was trying Ubuntu, when I booted the DVD for the 2nd time, it started correctly, but I still had the exact thing in some places, eg.: Applications list.
Tutorial: How to Install Ubuntu 13.04
Tutorial (mirror): How to Install Ubuntu 13.04
Specifications
Motherboard: AMD M2N68-AM SE2
Processor: AMD Sempron LE-1250 2.2Ghz
RAM: 2GB DDR2 RAM
HDD: 320GB HDD
Integrated video card: nVidia GeForce 7025/nForce 630a
Monitor: Samsung SyncMaster S19B300
Connection: Wired