First check that all plugs are correctly and fully in place.
Try some headsets or another set of speakers - see if the problem continues.
If so, start by right-clicking the small speaker icon in the lower right screen corner.
Go into Playback devices, find your device and check the setting, properties, configuration, etc.. everything that you can find.
All too easy to overlook some setting.
Could well be that you just need to correct or configure the speaker setup.