Avast Free will not install

[REDACTED]

First let me say I'm not very tech-savvy.  I'm running Windows 10 on a Dell PC. My Secure Line VPN stopped working yesterday - "Secure Line VPN has encountered a technical problem". I restarted the PC - no good.  Ran the Avast repair facility - no good. Uninstalled Avast via Windows, then ran the Avastclear.exe download. Attempted to reinstall Avast free but got "Download Failed"  Tried again - same thing. Went to Prodramme Data and deleted the newly created Avast folder and tried again - no good. Can any one help please?

[Asyn]

- Which version of Avast Free..?
- OS..? (32/64 Bit..? - which SP/Build..?)
- Other security related software installed..?
- Which AV(s) did you use before Avast..?

[REDACTED]

Hi, and many thanks for your response. To the best of my ability these are the details. 
Avast version 18.2.3827.0
OS is Windows 10 home 64 bit  version 1709
OS build 16299.309
Running Malwarebytes free plus Defender (tried turning off Defender and Malwarebytes but no luck)
Had Avast free since I had the machine - this is a re install.
It may be relevant to say that immediately before this happened I updated Malwarebytes free and was tricked into a 14 day free trial of Malwareytes Premium. The Avast Secure Line had been slightly defective before that but then ceased to work at all.

I hope all this is some help - it would be nice to re-acquire Avast if only to use up the remainder of my Secure Line subscription!
Thank again for your help.

[bob3160]

Clean Install of Avast:
https://goo.gl/4Ptzkf
If you need additional help with the Clean Install, watch this:
https://youtu.be/p-h3myRD51A

[Asyn]

It may be relevant to say that immediately before this happened I updated Malwarebytes free and was tricked into a 14 day free trial of Malwareytes Premium.

Regarding Avast & Malwarebytes, see: https://forums.malwarebytes.com/topic/200324-exclusions-for-avast-users/