An issue with the Atomic Shop in Fallout 76 was causing PCs to crash earlier. Fortunately, it looks like it’s been fixed.
“We are currently investigating an issue causing players on the PC Microsoft Store and Game Pass to crash to desktop when logging into @Fallout 76.”
“We've made some adjustments on our side and this issue is now resolved. Thank you for your patience! “
Log back and check if the game is stable again. Hopefully you’ll have no issues.