GRUB issue. black screen, blinking cursor

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http://askubuntu.com – so i installed ubuntu after windows was wiped out by destiny and everything was fine until i wasn't able to start ubuntu: it would stuck in a black screen with a blinking cursor forever. so i made a bootable usb and the trick is i can boot from usb, then restart my laptop and then and only then, it is able to boot from hard disk and i can access my archives and everything, until i turn it off and then i have to boot again from usb... etc. i am using 11.10 in a dell inspiron 1501 with an ATI RS482 [Radeon Xpress 200M] video card note. i already re-installed grub and updated it, which gave me a (HowTos)