Question About Installing OSes

I don't have access to a flash drive or SD card, but I need to put a different operating system on my old desktop. I have an idea that might work but I want other people's opinion. Okay...

If I create an empty partition, then put the iso on that partition, could I then overwrite the other operating system from the one I put on the other partition?

In my head, it works, but I've been wrong before. Is this a bad idea? or will I get errors? Anything helps!