When installing Ubuntu, I got the Install alongside Windows 7 option. Is there a possible way of me being able to transfer a file from my Windows 7 installation to Ubuntu? Also, are Halo: Combat Evolved and Minecraft compatible with Ubuntu?
In response to your question about moving files, yes you can. Just save the file somewhere on the Windows partition and then from the Ubuntu side, browse to it in Nautilus.
Minecraft is just a Java file. Just search around this site and you'll find instructions to run it.
In order to run games meant for windows, you'll want to use Wine. As for Halo, you can see here that it has a gold rating. Shoot [no pun intended] for versions 1.08 or higher since it doesn't have a CD activation bug.
Ubuntu can mount your Windows 7 partition, so simply clicking and dragging from the windows partition to the ubuntu partition within ubuntu should allow you to 'transfer' the file.
Minecraft is written in JAVA and thus runs natively in almost every OS, including Ubuntu.
Halo supposedly runs pretty well in WINE.
Minecraft is java based, so yes. Java is cross platform, and there is a java for Ubuntu.
Halo Combat evolved, well WineHQ claims that it's working with wine.
So yes on both questions.
And with transfering the files, just mount your disk and drag & drop the files.
In response to Minecraft, the Ubuntu Software Center has a couple applications for launching Minecraft. I've not tried any of them, but you can see them by searching for "Minecraft".
What I found was MC-Launcher ($2.99 USD) and Mini Minecraft Launcher ($4.00 USD)