I have recently installed the 64-bit version of ubuntu on my computer (64-bit) with bootloader installed to /dev/sda/, but for some reason the grub loader does not show up when I boot. The computer boots into Win7 without any prompt whatsoever. I only have one hard drive, and I have used EasyBCD to add a Linux entry, but when I try to boot from the windows bootloader, all I get is a grub4dos prompt. Any help is appreciated. Thanks in advance.
P.S. I have also tried Linux Mint, but that does not work either (the computer boots directly into windows).