Vista MBR issue

Sorry if this is a repeat post, but I have been trying to fix this for some time...

Ok, I partitioned 20gb from vista to give to PCLOS. went through the installation process, used the partition that i made for myself, but when my computer restarted, it stays at a black screen with GRUB on the top left. I am having a MBR problem with Vista, and since PCLOS obviously didnt install properly, neither that NOR vista is working. I dont have a vista repair disk, but downloaded one and it goes through the "loading files" phase and then shows microsoft corporation at the bottom, but hangs at the sky-ish colored screen. I have even gone as far as trying to install ubuntu, Fedora, and none are working the way they should (especially UBUNTU :x )I am completely at a loss. Any help would be HUGE.
Hi dacatz,
Your Vista loading problem with the skyish screen is directly caused by the MBR issue, so it's not surprising that it's not working.

The easiest way to fix this is by clearing the MBR (zeroing it out). Boot from the Ubuntu CD/DVD, and open a shell:
sudo dd if=/dev/zero of=/dev/sda count=1 bs=446
No. Get into the live CD environment, and open a shell to execute that command in.

Make sure that /dev/sda is the right drive though, first.