Even if the os is up to date, the os per se can't be a definitive measure of stability. Software is very fragile. explorer.exe will blow up to a 500mb gorilla. You can try monitoring the memory & cpu usage in task manager (ctrl alt del). If explorer blows up over 100mb, it's time to kill it and then, file, run, "explorer.exe".
I make a script that is triggered by a keyb shortcut for killing & running explorer while leaving all other apps alone. Another way is to log out & in.
What's your ram settings in bios? vdimm?