hello! im new to linux, and sort of to windows. ive been using mac. earlier, i had downloaded ubantu then used daemon tools to emulate it and it worked perfect and i was able to run everything. then, everything froze so i restarted it. when i rebooted it, it would start correctly, then turn all black with a flashing cursor. so i tried to uninstall it and reinstall it, and i get to the end of the installation then it does the same thing again. someone, please help!