I added a download manager today from your addon page. after which my Firefox would not run, although it is shown as running in Task Manager. I uninstalled it and re-downloaded the UK 64 bit version. Just before install ends when it gets to just a little housekeeping I get a system crash blue screen and the above message. I tried removing all Mozela files and registry keys but to no avail. I am running Bitdefender 2018 antivirus. I am stuck with Windows 10Pro build 1511 since upgraded stopped working after that, Microsoft could not find why, it always failed on the first preboot stage and resets back to 1511.