Can you post more details about your player? Look for the Firmware Info/Ver on your player's [Setup] menu and post details here. That will tell us what type of chipset it has.
If yours is an Actions chipset, you can try following this Knowledge Base Article here:
How to: Set sleep and power off settings
Most likely your player has a sort of 'sleep' mode enabled which means it go into a sleep more if not used. It does sound weird that it would after 2 seconds though.