At last I find the follow in the FAQ’S:

[ How can I uninstall avast!?

A: You can uninstall avast! just as any other software - using ADD/REMOVE PROGRAMS in Control Panel. There is nothing special about this. If any problem appears, use the avast! uninstall utility.

The exact way:

Click on START button.
Select SETTINGS → CONTROL PANEL (or simply CONTROL PANEL - it depends on your Windows version) → ADD/REMOVE PROGRAMS.
From the list of installed applications select avast! Antivirus and click on CHANGE/REMOVE button.
avast! setup starts. Select UNINSTALL and click on NEXT.
Computer restart will be needed after avast! uninstallation.]

I find the control panel with clicking on the list of installed applications and click on “change/remove” button,now I clicked on the area “repair”.

Note: the problem is not repaired!!!