I think my computer has a virus, I can't install avast

Avast Free Antivirus / Premium Security
1

when installing avast

Avast Antivirus installer is unable to continue because the
installer is corrupted or is forbidden to run on this machine.
For more information please see the Setup.log file.

           Reason: 1224 (0x000004C8)

i get the error

2

HELP ME

3

Have you removed ALL previous used antivirus programs using removal tools ?

Uninstalling other antivirus software. https://support.avast.com/en-us/article/uninstall-other-antivirus/

4

You should first check and properly remove other 3rd party antivirus software (not Windows Security) as stated by @Pondus.

If you have a poor internet connection there is a chance the installer got corrupted.
Have you tried more than once?
If true, maybe download and run the offline installer, from the link Avast provided here: https://forum.avast.com/index.php?topic=322940.0