|You can't update what ? |
Windows or AVG or ?
Your user must have administrator rights.
If it does, see this
"1. (Advanced) Set permissions to their defaults in the registry"
You must un-install AVG (in Control Panel - Add or Remove Programs ) before you install it again
If your AVG 2011 installation is corrupted and won't un-install, you can remove it with this AVG tool - AVG Remover 2011:
If you have XP Home or XP MCE, use the 32bit version. If you have XP Pro, most people DO NOT have the 64 bit version of it - use the 32 bit version of the Remover
NOTE that depending on what is wrong with the AVG software, the Remover may stall and seem like it isn't doing anything - in that case, WAIT for a while - it will complete running within 10 minutes.