Can't install an older version of Avast

[geervaas]

Hi, I have a question regarding older versions of Avast. You see, I have a slow computer and I get a very noticeable performance drop when I run 7.+ versions of Avast. A year ago, I updated it and had to start using the 6.0.1367 version again because my computer couldn't handle the latest one. Back then I managed to reinstall it just fine, but now I accidentally installed the newest version and now I'm unable to reinstall either the 6.0.1367 version or older ones because the setup insists in downloading the latest version. I removed all software and registry keys (including the HKEY_USERS one, though I might be forgetting something), and I even tried to reboot and install it offline but it keeps somehow "detecting" its version and trying to download the 8.0.1483 one.

How can I keep it from trying to install the latest version? Am I missing something?
 
Thanks in advance.

[RejZoR]

Download this (latest v6):
http://www.filehippo.com/download_avast_antivirus/11113/

1. Uninstall all existing versions of avast!
2. Use this tool to remove remaining files and registry entries: http://my.opera.com/rejzor/blog/2013/02/01/avast-cleanup-tool
3. Unplug LAN cable from your PC
4. Install the above avast! v6 from FileHippo and reboot the system
5. Reconnect the LAN cable

avast! checks for new versions during installation, but if you do it offline, it should install what it has in the installer. When you give it connection back, it will check for program update, but since it's set to ask for program updates, you can easily decline it.

But really, i recommend that you use the version 8. It's just better and if you think slowdowns are abnormal, post a bug report with as much detail as possible. Maybe there is indeed some sort of  a problem thats causing the slowdown for you. Using outdated versions of security software is not recommended for obvious reasons, thats why i recommend you to do so.

[geervaas]

Thank you, RejZoR. I'll try doing that.

About the speed issue: it's more because of how slow my pc is, I haven't seen any particular problem/bug, it's just that the newer versions seem more taxing and I'm currently stuck with this computer. I'll update it when I get a faster machine.

[RejZoR]

What components do you have? I've been running latest versions of avast! on quite low spec'ed PC's and it worked perfectly fine.
I mean, the scan engine is the same in v6 and v8 (apart from few things that shouldn't affect speed all that much). That's why i find it a bit strange...