Avast is using all the memory and CPU power on my laptop

Please help
Avast is using all the memory and CPU on my laptop.
I have scanned for worms and viruses.
I have updated the anti-virus software.
The (Windows Vista) laptop runs fine until I start the Avast services.
Any advice?
Thanks in advance
Patrick

Perform a repair of avast.
If that is not solving it, perform a clean installation of avast.

What settings are you using in avast.?
Scanner settings and filesizes can affect the computer resources.