Reply to Speaker problem iv just got

I have 2cdj 2000 and djm 400 mixer connected to pioneer s-dj08. But the problem is i only have sound coming out the left speaker. Was working fine when i had my laptop connected to it all but now iv changed to pc iv got this problem so i thought it was the software i was using on pc and changed the settings still same problem. So then i tryied just cds and still the same any idea what it might be ?