When i go to boot up ubuntu i get this... [GRUB4Dos 0.4.3 2008-06-03, Memory :638k/510M, codeEnd:0x41A38 Minimal BASH-like line editing is supported| and it gives me a dos menu and doesn't allow me to boot into ubuntu.

GRUB4Dos 0.4.3 2008-06-03, Memory :638k/510M, codeEnd:0x41A38 Minimal BASH-like line editing is supported

HELP.