How to run Avast security internet 2015 in Safe mode?

Hello, I need to run Avast Security internet 2015 in Safe mode but when I go into Safe mode after a boot it’ll not start! How to run it pls?

Thank you

Why do you want to run AIS in safe mode?
Very few drivers are loaded at the safe mode level.
Drivers are needed for avast to function.
You may want to schedule a “boot scan”.

I need it for my PC will shut down every time I try a scan in normal mode.

Seems you have a problem that need expert check

see instructions here https://forum.avast.com/index.php?topic=53253.0
attach Malwarebytes and Farbar Recovery Scan Tool logs … 3 logs total

below the box you write in here, see Attachments and other options

I think that is a feature has to be added if not already available, in Avast Internet security 2015

Avast boot scan has always been there https://www.avast.com/faq.php?article=AVKB132#

However it seems you have a serious problem since it normal scan dont work, so attach the logs requested

The boot scan is of no use at the moment since I need to use my PC for long other than scan it.

For the time being please attach the log results so that a malware removal specialist can take a look.
The quicker you get this done the quicker your computer will be back to normal.