I want to install/use JBoss 6.4.20.0 in my windows machine.Could you please suggest where I can download it.
Is there any support available for this product.
If you are developer, you can download and use JBoss EAP for development purposes for free through the Red Hat Developer program:
https://developers.redhat.com/products/eap/download/
There are downloads for older versions there, too.
EAP 6.4 is still supported by Red Hat, but you must have a subscription to receive support.