I've downloaded FRAPs and started recording a mission from renegade.
When I come to open it, the video has some parts where it freezes and most of the time its out of sync and I was wonder who can help me.

There's a setting to sync audio that needs to remain enabled, also, recording to a separate drive helps sometimes for the framerate.

For the seperate drive, if I install FRAPs to Drive D: (my renegade is on C:) will it help the frame rate?

Not so much, it's the output folder you want to have on a separate drive. Set the destination folder to the drive that fraps is not installed on.

Thank you very much for the help with the frame rate, the option for the sync with video has 'dont sync audio with video' I disabled that unless I need to.

When it says don't sync audio with video, you need the check out of the box. The way you said did it sounds like it's correct. Have you tried it? Is it better now?

'tis all good