Scanning

Does Avast have to run everytime the computer boots up. It is causing my computer to run slow for a longtime!

It’s better to solve what is going wrong…
avast needs some time to load, it’s normal some delay. It’s an important part of the computer security.
But, of course, it couldn’t take that long.
Please, post more info about your computer: other security programs, the antivirus before avast, do you use automatic logon?
Test if delaying avast services at startup will help.