Rough specs:
4 core processor (reasonable spec but not SOTA by any stretch).
4 GB DDR3 RAM (one of the reasons he's getting rid is this is the max)
1 TB hard drive
1GB DDR5 ATI graphics card (therein lies most of my woes).
Monitor is a 17" TV
I've split the HD into 300GB for Win7 (for Angry Birds, Lego Batman etc) and the rest is MInt 14
Problems:
Cinnamon desktop wouldn't sort the display out. Kept being squashed, stretched or way off centre. In the end, I installed KDE on it. That's now sorted and the display is the same size as the display... except that it's about quarter of an inch to the left of where it should be. I have a black bar on the right and am missing half the KDE logo.
I tried to adjust it through the display settings. I found the toggle left, right bit, but there's no indication of what I need to set it too. Plus, hitting "apply" doesn't seem to change anything whether I set it to 10 or 200.
Next. There's no sound. It works through the HDMI on Win7, but in either cinnamon or KDE, there's nothing. This is a problem. The Linux desktop is there mostly to serve as the front end to a media player. He want's Star Wars and Doctor Who.... I have tried to get it through the line out as well. Nothing. Nada. Zip.

Display is slightly rippley. I take it this is to do with the ATI card. Anyone recommend which driver I should go with?
Grub is off centre as well. I can tell which option to pick, but it looks wrong.
And I know this isn't linux, but Angry Birds (original) went on fine. But ever since I did the update, it crashes on loading. I've uninstalled, grabbed a new file from the Rovio site. Reinstalled from there, from disc etc. Nothing. It won't load. Angry Birds seasons is fine. Angry Birds Space is fine. Angry Birds Star Wars is fine. Angry Birds isn't.
Oh, and the discs are all originals bought from shops. I can't seem to find a way to fix this...
Any ideas on any of this?