hi ,i have downloaded avast 4.6 in oct’05 and now its showing that avast is out of date when i login the sys .plz tell me how to update it.
You should configure it to this…
The default settings are Automatic virus databases updates and Manual program updates.
Open program settings (right click the ‘a’ blue icon) and check the two Updates tabs of settings 
Do you use a firewall?
What is telling you avast is out of date?
Check the system date especially the month and year, double click the clock in the system tray. If it is incorrect correct the date and you should e OK.