Hi guys... I did a quick search for the topic and dint find anything too similar...
I've got Windows XP Home SP3 on my computer (an HP) right now, and the family computer (Acer) came with XP MCE 2005. The Acer came with a disk, with... yeah.. MCE. But it's sealed, never used.
So could I technically use the Disk and install it onto my computer?
And should I just reboot the computer with the Disk inside the drive?
Before you install your OS you will need to partition your hard drive; just follow the instrustions here.
Then you should reboot your computer and go into the BIOS(try pressing F8 or F10 to get into the bios). From there just make the cd drive the first boot device. Then just place your cd into the drive and save your new bios settings. You should be able to go through the steps and install it on your new partition. You might have to google for drivers but that's just part of the learning process.
It's got Media Center...
and I've done what you said, Nick... unfortunately, when I boot-up, it goes "You can't install Windows Media Center as your computer is not an Acer"
It looks like you can easily donwload media center since it's freeware, like here. Or if you want to try something different then you can give xbmc a try.