cant delete, upgrade, uninstall avast

Hello, i am from chile so my english is not too good

i have avast version 4.8.1229, windows XP

My avast is not updating since VPS 081029-0, i keep getting an error message that i have to upload my VPS, i tried to do it manualy but doesnt work and it is supposed to do it automatically.

At about avast it says that i have this VPS since 29/10/2008

the key is working up to 01/01/2010 and the clock/date of the computer is correct

i tried to uninstall avast to install it again but it doesnt do anything

any helps please

Already answered here:http://forum.avast.com/index.php?topic=43024.msg359696#msg359696

Best to post a question in one place only, please.