OEM is just an original Windows disc. No additional drivers, no additional HP software pre-installed.
You can get an OEM ISO from here:
Legal Download from DigitalRiver: Windows 7 SP1, 13 languages
And either burn it to a DVD or run it from a USB using Microsoft's USB tool.
Pick Home Premium 64bit. You can then use the key on the bottom of your laptop so that you can activate it.
So you can either do that, or you can just order the recovery discs from HP and have them sent to you.