Itunes. i don't know how to get back to my old version of itunes, b c i just downloaded the

Question

i don't know how to get back to my old version of itunes, b c i just downloaded the newest version, and my computer is too old for the newest version, so it downloaded it, but now my itunes won't even OPEN bc its saying my computer is too old..........so my itunes will not open anymore. is there any way to get back to my old version???