Cant Update?

You see, Windows say that Avast isnt Up-to-date.

I tried right-clicking the Avast Icon> Updating> iAVS update.

The screen freezes, then it returns to normal, nothing happens?
I also tried downloading the manual update. It says Error, with some codes, i forgot.

I tried uninstalling it, with Control Panel>Add/Remove programs.
I click Change/Remove of Avast, it freezes, then returns to normal, nothins happens.

Please help!

What OS do you use (XP, Vista, other?)
Was there another AV/security suite installed on this computer prior to Avast?
Any history of malware (virus) before this?

Also, which is your firewall? Any other security program is still installed?