1. Install 3DS MAX 2009.
2. Start 3DS MAX 2009 and Select Activate the Product when ask for activation, select Enter an Activation Code
Use as serial :
653-12354321
or
666-98989898
or
666-69696969
Write down the request code.
3. Fire up the xforce keygen and generate an activation code based on your request code.
Continue the registration process.
Copy and paste your generated activation code ..
Restart MAX
4. Enjoy!