I have a Raspberry Pi 3b+ and a Windows Laptop, through which I have downloaded Pidora and made a bootable SD Card with Etcher Software. When I try to boot my Pi using this SD card it is not doing anything at all. What may I have done wrong here in this process? The same problem also happens when using Ubuntu Mate.
You do not tell much what you have done to flash the SD Card except that you used Etcher on a MS Windows PC. Yes, Etcher is the preferred software for flashing. For testing I suggest first to try the official supported operating system Raspbian Buster. It is known that it works. If it is also not booting then you are doing something wrong with Etcher and flashing or your the RPi 3B+ is broken. If it boots then the other images does not support the RPi 3B+.