Time consuming startup scan

Am using Windows XP
Everytime I start computer Avast does a scan
How do I stop this

What makes you think that avast! is performing a scan?

If it is indeed an avast scanning, if you press F8 when starting Windows and select ‘Last known good configuration’ from the boot menu, the boot scan should not be started.

Firstly thank you for responding to my query…
When you put the mouse over the spinning icon on the system tray at bottom right message appears…
“On Access Scanner 7 provider(s) total, 4 running”
then when finished it comes up with the blue box stating that “Virus database has beed updated”…
Very annoying

"Virus database has beed updated"
this will pop up when your virus database is updated and is normal and also important to update your avast.
"On Access Scanner 7 provider(s) total, 4 running"
click the spinning blue icon at the bottom right and after that there will a program and click the Details...>> and click start to on the non-running providers (For Outlook/Exchange you doesn't need to turn it on because it will on when your using this program.)

What is very annoying, that the update shows a message if finished?

You should be able to deactivate this message:
rightclick on the avast-symbol in the taskbar and choose settings → select update in the left column → now click details in the lower right corner → there you can choose if you want to see a message or not (see the picture)

Strange… did you change avast settings? I would believe on 6 of 7 providers running. The one that is not running is generally Outlook plugin, that starts when you open (run) MS Outlook (not the Express).

Juds, I think what is happening, and it happens to me too, is that during the time that your system is off the good folks at avast make an update available. When you boot up your system avast looks for an update and finds the new one. Updates are done very frequently so it is common to find a new one if your system is off overnight. For me the annoying part is that the update process really bogs down the system. Fortunately it doesn’t take very long but during that time it is really bogged down. You could change the settings for updates to be done manually only. Then the bogging down will happen only when you want it to happen. But you need to do the manual update at least once a day.

When you hover the cursor over the icon in the system tray it is telling you that the on-access scanner is alive with 4 providers running - but that does not mean it is actually scanning anything at that very moment. I have the “animate the icon” option selected so the avast sphere icon in the system tray rotates when actual scanning is happening. I also have 4 out of 7 runnning. I disabled Instant Messaging, Outlook, and P2P since I don’t use any of those things.

Hope this helps,
Larry