Well if you look at your second image the CPU usage is 58%, yet the avastSvc.exe is only using 6% so it appears to be scanning something (what is the $64,000 question) now whilst it is scanning it will also be using memory, but that should fall back to more normal levels.
Are you able to find what other applications are using the bulk of the 58% CPU as when applications are active, this will be triggering a resident on-access AV like avast to scan that content, with a resultant increase in resource use. Your second image actually show the avast tray icon in mid rotation, indicating it is scanning.
Strange that your first image shows that avast has a problem, the Red blob with an X over the avast tray icon. This is effectively saying that avast isn't running ?
Given that you appear to have had a slew of other AVs installed, this could be down to other AVs still installed or remnants remaining. It could also result in high/higher RAM & CPU usage.
How did you remove avira on your system ?
Your dds.txt files shows avira in program files c:\program files\ARIVA FREE VERSION 12; c:\program files\ARIVA FREE 2013. It also shows EMSISOFT TRIAL 7.0 in program files. All previous AVs installed have to be uninstalled and I would go further and run their specific removal tools after the uninstall, see #### below.
I also see c:\program files\NEWER MICROSOFT SECURITY, not sure what this is, MSE perhaps ?
####
Uninstall possible remnants of previously installed AVs see,
http://singularlabs.com/uninstallers/security-software/, this has a collection of manufactures removal tools, so that should remove any remnants, registry, etc.