What exactly are you trying to accomplish, it seems as though the HDD install is working good, is that correct?
Can you post some more info about the pc in question. This is an old laptop with some common issues installing linux so it will help to have more info. If you can boot into Xubuntu, open terminal and copy this into the Terminal: inxi -Fx and hit Enter. This will produce a nice output of what is on your laptop. You can Copy Paste that here.
If you can't get help and you don't mind distro hopping, you could try out another distro, one better suited for older equipment.
You could try these out but I am still new to all this so cannot predict the outcome.
When you boot at the main menu press F6 and at the end of the line add the boot option(s) noapic.
initrd=/install/initrd.gz quiet -- noapic
initrd=/install/initrd.gz quiet -- noapic nolapic and see what happens.
Be sure to read my Disclosure in my Signature first. Or wait for some better info from Al000 or someone else.
So what do you have 15.04 or 14.04?
Is this the same hdd that you have Windows 7 on?
A BIOS Update might also help from what I have read.
Created by Mike_Walsh
KDE, Ruler of all Distro's