I was recently given a retired MacBook pro from my work. It's a 2009 A1278, originally shipped With OSX Leopard 10.5.7. When I try to reinstall, it asks me for an Apple ID. Nobody around the office recalls what that might be, since it was 8 years ago when it was originally purchased, and the records from that time were messy at best, and we've gone through a substantial management change since then as well.
I'm considering buying a new install disk from Apple, but they don't seem to sell 10.5.7. So my main questions are, how do I get around this requirement to enter the Apple ID and re-install the OS, and if I purchase a disk that's a higher version than what was factory installed, will I be able to install it?
Any other details you have would be appreciated. I just want to make this thing compute again.