Hello, Dean and welcome to the forums!
Unfortunately, we are going to need a bit more information before anyone can help. First, read the top sticky post on this Board, the one labelled ' Please Read This Before Posting!' and get back to us with the information requested.
In addition, within Video Studio, right click on one of the captured files and copy down ALL its properties here please. In particular, we need to know the audio properties of the captured file. It is possible that it is Dolby audio and the trial versions do not contain the Dolby codec for license payment reasons.
Finally, we definitely need to know exactly which make and model of capture card you have. Some (many?) are made by manufacturers who tweak the software they provide (including older versions of Video Studio) so that they work with their hardware. However, they don't share the tweaking secrets with the software manufacturers so that more recent versions of the software will not work properly or at all with the hardware.