Format and fresh install Is there any option for android phones to format like we do in computers and fresh install with a new OS?

I have searched a lot but all are going for custom ROM, and I am not interested in custom ROM, as they are basically a few tweaks. I want to install new OS in my phone like we do in our PC. Can anyone help?
If you just want a fresh start with your phone, you don't need to reinstall the OS at all, because OS files and user apps and data are stored separately. In normal use, the OS partition is read-only. All you need to do is a factory reset. This wipes all user data and apps, but doesn't usually touch the SD card. The process to follow is slightly different for different phones, but there's usually two ways: either reboot into recovery mode, which has a "factory reset" menu item, or from Settings → Backup &amp; Reset.