If you haven't already, make sure to reseat that ram and maybe check thermal temps. Since you can't get it to work in safe mode, maybe try linux distro in a differe HDD and use that to boot to troubleshoot further.
I don't really mind, but OBS isn't necessarily super resource heavy, but I would recommend a decent CPU. You could also look at some videos on how to optimize your computer for OBS. Do you prefer a laptop or desktop? Also what is your current system specs?
50 degrees C isn't enough to cause damage. If things get to 80 there may be an issue. Have you changed any settings or downloaded any updates recently?
I'm no expert here, but make sure you have the right amount of thermal paste and that the cpu and the cooler are seated properly. Are those temps under load or while idle? They seem to be a little skewed.
Typically building a pc is a good cost effective idea, but you don't have much need for power if you're only recording reactions. Could go with a decent prebuilt systems and buy a better webcam.
32 bit systems have low ram limitations. No matter how much you add to a 32 bit system, it will never go above a certain point, the OS cannot use it. You will need to upgrade to a 64 bit version of your OS.