No Avast icon in taskbar. No Avast on bootup?

Hello,
I have read help, and searched here on the forum, and can’t find an answer.
My taskbar icon has disappeared and Avast is not starting automatically on boot up.
I have started Avast and checked setting for icon but it does not show.
Windows Defender shows it is not on startup list. But, is running after I open it manually.
I have a Desktop with Windows XP home.
Avast- download658.avast.com (74.55.137.50)
I changed my ISP to ATT DSL a few weeks ago, but Avast was OK till today.
How do I get Avast back to opening with startup?
How do I get the taskbar icon back?
I am a novice user.
Any help would be greatly appreciated.
Thanks.

Try a repair. Start > control panel > software > avast > add/remove > repair.
Report back here after doing so.

Hi,
It said successfully updated.
Would that update ti back to the old settings?
thanks

Well, is the problem still there or not?

Hello,
I think that the problem is fixed.
I rebooted.
Icon came back.
Hover over the icon shows providers running.
Windows Defender shows Avast running and on startup list.
I think that it is OK.

Did I do something to cause this?
Or, does this just happen sometimes?

Thanks for your help.

horseman1212, just to be sure, repair your installation:
Go to Control Panel > Add/Remove programs > avast! antivirus > Remove. Then choose Repair function in the popup window (Repair).