I'm now using ubuntu from USB, and I'd like to install ubuntu on my hard disk. I tried the option of removing Vista while installing ubuntu. However, near the end of the installation process (presumably the end because I can see some slideshows on how to start using ubuntu), the screen suddenly goes to black with white words running around on it. Soon the computer shuts down. After that, restarting leads to a black screen with only a small white cursor on the top left corner. The cursor keeps blinking and nothing happens. I found that I can alternatively choose to boot with USB by hitting F12 just when the computer starts. So I tried to reinstall ubuntu by running ubuntu on USB. One of the options of installation is to update ubuntu 11.04 to ubuntu 11.04, so it seems the ubuntu is already installed somehow. Anyways, I tried both update and delete and install option but the same thing happens as the 1st time (sometimes before reaching the end), while I still cannot start my PC as ubuntu (without USB). How may I install ubuntu properly?