I have avast 5.0.462 free, the e-mail is from Register@avast.com.Here are the instructions,
** For users of avast! Free Antivirus v5.0 (orange ball) **
1. Highlight the license key above, then right click on it and select "Copy"
2. Right click the orange "a-ball" in the bottom right corner of the screen, then left click "Registration information"
3. Click the "Insert license key" button at the bottom of the screen.
4. Right click in the empty Registration box then select "Paste"
5. Click "OK". Your license key is now inserted and the program can now be used free of charge for a further 12 months.
If you experience any difficulties inserting the license key, please click here for more help:
http://support.avast.com/index.php?languageid=1&group=eng&_m=knowledgebase&_a=viewarticle&kbarticleid=459 they then give me a license key.