Q: My apple account has been blocked cuz I tried to purchase apps but I forget the answers of the security q.how can I activate it ??

Reset Security Questions

http://support.apple.com/kb/ht5312

If you still have problem, call Apple to help reset your Security Question.

http://support.apple.com/kb/HT5699

See Kappy’s great User Tips.

See my User Tip for some help: Some Solutions for Resetting Forgotten Security Questions: Apple Support Communities

https://discussions.apple.com/docs/DOC-4551

Rescue email address and how to reset Apple ID security questions

http://support.apple.com/kb/HT5312

Send Apple an email request for help at: Apple - Support - iTunes Store - Contact Us http://www.apple.com/emea/support/itunes/contact.html

Call Apple Support in your country: Customer Service: Contacting Apple for support and service http://support.apple.com/kb/HE57

About Apple ID security questions

http://support.apple.com/kb/HT5665

If you forgot the answers to your Apple ID security questions

http://support.apple.com/kb/HT6170

 Cheers, Tom