According to Mactracker, you have a 15" MacBook Pro Mid-2009 model with a Core 2 Duo processor. This is considered obsolete by Apple, it will support up to OS X 10.11.6. There is a DVD drive or it can be booted from USB or Firewire drives.
This article has a list of startup key combos:
This article has options for recovering an Intel-based Mac:
I'm not certain if your machine has all of the recovery options listed, you'll need to test and see. If you have access to another Mac, you can download the OS X 10.11 installer and make a bootable USB drive or DVD.