Black screen after boot in Ubuntu 9.10

          I installed Ubuntu 9.04 with wubi in Windows, and it worked just fine. I decided to upgrade to the 9.10 version, I restarted the computer after the upgrade. When it booted I just watched the white Ubuntu logo, and after that a black screen appeared. The OS doesn't load, because I cannot hear any sound, and if I press ctrl+alt+f1...6 (to load terminal mode) nothing happens. So I decided to uninstall it from Windows, and I downloaded the 9.10 cd, and make a clean installation with Wubi. It happened the same (the os makes nothing). I've also waited some time, to see if something happened, but it was the same. When I booted from the live cd, and chose to try the OS, also the black screen appeared, and nothing happened.

          My computer is a HP Pavilion dv2000 with an Intel Dual Core Processor, and an Intel 945 graphics card. I hope someone could help me. Thanks.