[ubuntu] ubuntu installation error

Hello,

I asked my friend to install ubuntu on my hard drive (the cd drive on my computer does not work), he took the hard drive and tried to install ubuntu on his computer, but he could not install it, he got all the files on the hard drive, but it does not boot up.
I tried re-installing ubuntu, but I can not delete the files from the hard drive and the other computer which I am using does not even recognize it!
Is there a way to delete the files?

Thank you in advance,
Victor