DJM 750 k Recording

So a couple of days ago I got a new laptop, a Acer Aspire 3. I went from a 2 year old MacBook Pro. I'm a DJ whom took about a year break because of a car accident. So I'm looking to go back to DJing and atm I'm looking to record a mix.The USB option does recognise and it says it's recording both on Audacity and Acoustica Mixcraft, but when I play back the files they are completely silent. Also I use Traktor and Audacity says an error (something about sample rate?) I'm sure there's something very simple that I just haven't configured, admittently I'm a bit ditsy... :P If someone could help troubleshoot this that'd be really appreciated <3