Can anyone help find the culprit?
Zipped mini-dump attached.
It`s difficult to be sure from only one minidump.
For reference only. Your minidump crashes at CnxTgP.sys. This is part of your Conexant modem drivers. It also references wbtray.exe. This is the WinBackup 2 Traybar.
Uninstall Winbackup and see if your system becomes stable.
Try updating the drivers. If that doesn`t help, maybe try a different modem.