If you use WDRT, WP8.1 will be installed and you must download wp 10 and if you Hard Reset via settings app, you'll stay on current updated version with all apps reset to defaults.
Make sure your OS and FW is updated to latest version. Just do a soft reset before charging the device and repeat it after a full charge to keep the phone in tip top shape.
Its been a long time, I've visited WC. The title says it all! Did MS enable the feature of clean installing W10M on bricked phones for older lumias instead of WP8.1?
Use AIDA64. Navigate to Sensors section and this is for testing Light sensor, Just take a look at Lux readings. As for Prox. sensor the method described by @gpbernando is the easy way.
Same here, couldn't take calls and soft reset wasn't working and even a shutdown too. Then I came across a thread where they mentioned a combination of Volume Up rocker and start button would disable Narrator.
Move all apps to phone memory and pull out the sd card. Plug into the PC and run chkdsk to fix Filesystem errors. Do a Hard Reset and start w10 from fresh w/o restoring data.
Try opening all the open all the apps and then turn off unneeded background apps, such as Photos, WhatsApp, Block and Filter(If you're using Truecaller) etc.
I went into Notification, scrolled down notification sounds and then reverted back to default soundset, that fixed it for me. But there's a catch you must manually update this build after build updates. Hope this helps!.