Soldato
I'd just start with a fresh windows install to see if that solves the issue, then replace the junk PSU, before getting a whole new system. Current spec is more than enough for minecraft and roblox.
If those don't sort it, then you're looking at motherboard or memory and probably you'd want to just get rid and try new. Keep the recently replaced Psu, though
If those don't sort it, then you're looking at motherboard or memory and probably you'd want to just get rid and try new. Keep the recently replaced Psu, though