Hello ,
I ran into a registration problem and hoping someone could help. 
I bought a 3-year 1 PC package before and it should be valid until Nov. 2015. However, after I uninstall and then reinstall my avast internet security software, I just couldnât got my authorization back. What should I do to fix this problem?
really appreciate for your help!
The original license.avastlic license file should still work as it did before.
Are you saying that A) it doesnât work, B) you havenât retained a copy of it or C) something else (please expand) ?
If it is B) above then you can try the Resend avast License http://www.avast.com/resend-license-paid.php, you will need to enter the email that you used when purchasing the license, e.g. the one that the original email with the link was sent.
sorry for not giving a clear description. Iâve tried to insert my license file but keep getting the message that said âUnable to insert the license file. The license has expired.â I also try again to insert the activation code I got before, but itâs not working. The problem is that my license should be valid until 2015.
ps. I purchase this software via a dealer not online purchasing.
Check your system date, day/month/year and adjust as required.
If it is correct try a repair of avast:
XP - Add Remove programs, select âavast! Anti-Virus,â click the Change/Remove button and select Repair, click next and follow.
Vista, win7 - Control Panel, Programs & Features, uninstall a program, select âavast! Anti-Virus,â click the Uninstall/Change and select Repair, click next and follow.
You may need to reboot after the repair.
Purchasing through a dealer may complicate this a little as I donât know how they are recorded, with a view to using the resend license option I suggested.
Are you able to contact the dealer ?
Just as what u said, I canât get my license resend due to purchasing from a dealer (Avast doesnât have any purchase record) and canât contact the dealer for some reasons. It really makes me a headache. 
Not sure what else to suggest, you could try the on-line contact form, http://www.avast.com/contact-form.php?loadStyles for: Sales inquiries.
Try and give as much information as possible from your transaction from the dealer.
If the dealer was an avast authorised reseller then it may be possible to track the purchase from receipts, etc.
Hello,
Thanks for your suggestions and support. I finally got help from the avast support team! Thanks a lot! 
Youâre welcome, glad I could help.