Q: hi i lost my reformat disc for macbook pro os x v10.6.3 build 10D575.how to download it from apple software

If you need to purchase Snow Leopard you can still purchase a copy from Apple's online store's telesales agents.[1-800-MY-APPLE (1-800-692-7753) or Customer Service and Sales Support at 1-800-676-2775.] Ask for a Sales Representative.

Third-party sources for Snow Leopard are:

Snow Leopard from Amazon.com

Snow Leopard from eBay

After you install Snow Leopard you will have to download and install the Mac OS X 10.6.8 Update Combo v1.1 to update Snow Leopard to 10.6.8 and give you access to the App Store.

Contact Apple and for a Nominal Fee... Request a Replacement Disc...

Be Sure to have your Serial Number handy...

Contacting Apple World Wide for Support and Service

http://support.apple.com/kb/HE57