I have a 2006 Macbook 13″ with 1GB of RAM. When I try to install Snow Leopard on it, it says “This OS X cannot be installed on this computer.” Why not?
Your macbook is too old to support Snow Leopard. If you really want to upgrade to Snow Leopard or above, consider buying a new computer
If you have a power PC chip then you are going to need to get a new computer. Snow Leopard only supports the i series of Intel chips which come standard on all Mac's now.
It means your MacBook doesn't support the Snow Leopard, and Snow Leopard supports the MacBooks since the end of 2007, but there's a way to hack the SL on your Macbook - you can make Hackintosh on your Macs. It's true, Hackintosh isn't exclusive to the PCs, it works on any Mac. My Macbook 2008 doesn't support the OS X 10.8 Mountain Lion and I made Hackintosh 10.8 on it and it worked for me. But I own a Mac mini 2011.
If you will be frustrated to install SL or Hackintosh on your MacBook, I suggest you replace for the end 2008 or 2009 or 2010 Macbook. Their prices have already decreased quickly since the upgrade of MacBooks 2012.
Snow Leapard only runs on 64bit architecture I _believe_ (if memory serves)
http://support.apple.com/kb/HT3696 How to tell if your Mac is 32 or 64 bit.
You should have no problem (I have approx. same specs), but we need more info. How are you trying to install SL? Can you boot from the CD? etc.
check out these links , may help u out !
Which media are you using to install Snow Leopard?
If it's a Installation DVD from another device it won't work as those DVDs are locked to the model they shipped with.
Mac OS X v10.6 Snow Leopard - Technical Specifications
Snow Leopard does not support PowerPC-based Macs (e.g., Power Macs, PowerBooks, iBooks, iMacs (G3-G5), all eMacs, plus pre-February 2006 Mac minis and the Power Mac G4 Cube), although PowerPC applications are supported via Rosetta, which is now an optional install.
Some ways of running Mac OS X Snow Leopard on certain unsupported hardware have been discovered. Users who have access to supported hardware have installed Snow Leopard on the supported machine then simply moved the hard drive to the unsupported machine. Alternatively, the Snow Leopard Installation DVD can be booted on a supported Mac, then installed on an unsupported Mac via the Firewire Target Disk Mode.