Q: I have a macbook pro 15" 2007 version 10.6.8 and try to up date to mavericks and it's not allowing too. what should i do?

What does it tell you. If it says it isn't compatible, then you don't have a mid/late 2007 MBP. You might have an early 2007 MBP, which cannot run Mountain Lion or Mavericks.

You can check here to see exactly which MBP you have: http://support.apple.com/kb/ht4132

If you hold down the Option key and select System Profiler from the Apple Menu, it will display the model identifier under the Hardware Section.

It must be a macbookpro3,1 or later.

Then your Macbook Pro is not capable of running Mavericks. You need a 64-bit EFI which yours lacks.

At the most you can install Lion. You'll have to contact the Apple Store to purchase a download redemption code for the App Store. You're probably better off with Snow Leopard.