Full scan at switch on?

[system]

Yesterday I got a new laptop and as usual I installed Avast as my Anti Virus.
Restarting the machine…there is something badly wrong.
Is there an option on Avast to scan the machine at switch on?
The machine comes on but I cannot use any application and its as if there is scanning going on in the background.
I was going to re-install Avast but even if I go to safe mode and ask the machine to reboot to the last time it worked correctly the egg timer stays on on the bottom line and on the main screen the pointer has no effect?
I have to use the on/off switch to switch off?

Any suggestions please?

Keith H.

[Lisandro]

@keith h post:1

Is there an option on Avast to scan the machine at switch on?

If you’re saying that there is a blue screen with avast scanning, yes, it’s the boot time scanner of avast.

@keith h post:1

The machine comes on but I cannot use any application and its as if there is scanning going on in the background.

When? After you did logon or before (the blue screen)?

@keith h post:1

I have to use the on/off switch to switch off?

How to disable scan at boot?
Could you please start regedit, go to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager, select the value BootExecute and export it to a file? If you could post the file as an attachment here, I would like to check what could be wrong there.