Nevermind! I found the solution to the problem.
I installed Minecraft.msi instead. I had an error installing which said:
"Unable to start the Minecraft Runtime Environment. This is most likely caused by a corruption. Please try to reinstall minecraft"
I was told then to delete the "runtime" and "game" folders, and try installing it again... which it worked! Now I can play Minecraft again, for now. I will have to get a new computer soon with better hardware.