".. started to play around with it for a while .."
What were you recording? The site advises, "Please note that HyperCam is not intended for re-recording of other video clips from the screen (e.g. playing in Media Player, RealVideo, QuickTime etc.), .." click here
Have you looked at their FAQs? click here
You could try using Unlocker click here to release the file and allow you to delete it.