avast 5.0545 show expire but register show next year

what happened with my avast 5.0545 (free edition) show expire while register page who next year

date of registration - 1 May 2010
expire - 1 May 2011

If the system date is wrong, this can happen.

system date & clock is OK. could my computer infect by any virus that disable avast?

Don’t hope so…
If you want to check use free Mbam: http://www.malwarebytes.org/mbam.php
asyn