Kubuntu and Ubuntu

i had a virus on my comp so i cleared the HD so then i wanted to try linux. i download ubuntu, try to load, cant. try to load kubuntu, wouldnt work. it always gives out the samer error! about GRUB. idk wat that is. but it says "installing boot grub loader (hd0)" on 94% of installation.
before i state error, i try to use the first option of the CD i booted start or install... wont even work after it has the load bars with kubuntu/ubuntu above it. on kubuntu it turns my screen off and ubuntu looks wierd. but i can run them in safe mode.

But error is:
Kubuntu: executing grub install (hd0) failed
This is a fatal error

Ubuntu: GRUB failed (dont remember exact thing for it but it says something about GRUB on 94% for both. >.> plz help. (using diff computer right now.)

GRUB is the bootloader, that is the piece of software that is being called after the BIOS has finished booting. The bootloader's job is to make the OS boot that you want to boot into. GRUB can boot virtually every OS, but when it's not working like in your case you can't really do anything with your computer.

In my eyes, the GRUB installation on the current Ubuntu/Kubuntu/Xubuntu CDs is flawed. I wasn't able to finish a Xubuntu installation on my mom's laptop because GRUB refused to install properly. However, since GRUB is always the last thing to be installed when installing a Linux OS, I simply aborted the installation and installed GRUB manually into the almost finished system. You can read how I did it in saikee's great thread on booting tips.