Yes, leave the media card out and run the device.
Did you move the card from an older BlackBerry to this 8900?
You might read this: Fix for Media Player Not Scanning For Music, Stuck on Scan, or Constant Reboots
Otherwise, do you have many applications running in the background OR an open browser on an active webpage? If so, close them. Press your Menu key > Switch Applications and see what is running and choose each application then > Menu > Close or Exit.