Choose About this Mac from the Apple menu and check the processor.
If it's a Core Duo Mac, click here, install the DVD, and run Software Update.
If it's a Core 2 Duo or better Mac, follow the Core Duo instructions, and if desired, open the Mac App Store and try downloading 10.9. If you get told it's incompatible, go to the online Apple Store and order a download code for Lion 10.7.
First we need to know which one of the 9 different models of MacBook you have. To see which model you have go to the Apple in the upper left corner and select About This Mac, then click on More Info. When System Profiler comes up check the Model Identifier and post it back here.
The Early 2006 model 1,1 Core Duo can only run a maximum of 10.6 Snow Leopard.
The models Late 2006 Core 2 Duos 2,1 through Early 2008 4,1 can only run a maximum of 10.7 Lion.
The Late 2008 model 5,1 Aluminum Unibody through the Mid 2010 White Unibody model 7,1 can run 10.8 Mountain Lion and 10.9 Mavericks.
The 10.6 Snow Leopard DVD is in the Apple online store. You can get it for $19.99. http://store.apple.com/us/product/MC573/mac-os-x-106-snow-leopard After you’ve installed that then download the 10.6.8 combo updater to finish it off. http://support.apple.com/kb/DL1399 You will need to be running 10.6.8 to access the App Store to order Lion, Mountain Lion or Mavericks.
System Requirements for 10.6:
- Mac computer with an Intel processor
- 1GB of memory
- 5GB of available disk space
- DVD drive for installation
- Some features require a compatible internet service provider: fees may apply.