If your machine supports it is the first question:
Call or visit an Apple Store or check the online area for "redemption code". It costs $20 and is sent via email. You use the redemption code in the App Store of your 10.6.8 machine to download Mountain Lion.
Check that your computer is compatible with Mountain Lion/Mavericks.
To check the model number hold down the option/alt key, go to the Apple menu and select System Information.
- MacBook (Late 2008 Aluminum, or Early 2009 or newer) model number 5,1 or higher
- MacBook Pro (Mid/Late 2007 or newer) model number 3,1 or higher
Check to make sure your applications are compatible. PowerPC applications are no longer supported.
Thanks for your suggestions. My mac book supported Mountain lion.
I contacted Apple customer care and they informed me that they stopped the "redemption code"... long back and I was referred to a Apple Retailer in India. He is charging too high 2500 INR (almost 40$) double than in US.