EDIT: Let me correct myself, it is free but restricted, sorry. The video capture is capped to 30S unless you want to pay for it. Here, I came across this site. Perhaps it will get you started.
Fraps, Can be HD it records at the resolution you play at, so say you play at 720P/1080P then it'll be either 720P or 1080P, I Believe it Costs about $30 USD so like £20 (Correct?) Anyways its the best recording I know of.