Fraps is fine, it has a free version which I suggest you test before you go and make the purchase. (it’s got some limitations and it adds a small watermark to your video saying you’re using the free version, but that should be good enough to find out if fraps works for you). Fraps is widely used so I can’t imagine it wouldn’t work in Windows 8. If it didn’t you should be able to find plenty of reports on the internet on that.
There are several others, each have their pro’s and cons on video quality, filesize etc.