am using avast version 5.0.677. it says that curent registration will expire on 4/1/2011
what does it mean?? and what should i do to extend the registration???
It rather depends on a) what version of avast you are using, free/pro/ais and b) the date format used on your system, the info below assumes that you are using avast free.
System date format:
If it is mm/dd/yyyy then you have plenty of time and can follow CharleyO's suggestion.
If it is dd/mm/yyyy then you are inside the 14 days and should be able to re-register, through the avastUI, Maintenance, Registration section; or off-line registration method as SpeedyPC mentions.