What Slingbox are you using? Which Slingplayer/device? When you say the box 'resets itself' what do you mean, does it just disconnect, or reboot, or need setting up again? Are you watching remotely or over a local network?
You need to give far more information if you seriously want someone to help you.
Describe in detail your setup, and what exactly you see on the screen, what the devices do etc.
Give yourself half a chance!