I installed Avast 4.6 last week on my new computer and had no problems until yesterday when a Windows Security alert says my Avast is out of date. Then the Avast icon on Toolbar pops up and says it may be out of date so I run the update and it says it is already updated. I tried uninstalling and re-installing but it still happens. Any suggestions? Thank you in advance!
Check your system date, especially the Month and year.
This may sound stupid but how do I check the system date and time, do you mean where you change the time on the toolbar?
Questions are never stupid…
Just double click the clock on the task bar.
Check specially the year of the date…
I think that worked, it was on 8/25/06 for some reason and when I re-booted I didn’t get any pops up of it being out of date! Thanks so much!
Some virus do this…
I suggest a full scanning with avast and other antispywares that you have 
Glad we could help, welcome to the forums.
Something to look out for in the future (excuse the pun) ;D normally we only see out of date meaning past dates not the future. As Tech mentions some malware might do this to try and circumvent an AVs protection, do the scan he suggests.
However, since the warning is from the windows security center, yet avast reports up to date when you check for updates, it is likely avast has been running fine and you should be OK.