All was working fine till I left my Pi 3 b+ board turned on for around 4-5 days along side windows on my monitor.
Now, when I connect power to it, only red power led glows constant red. Yellow led doesn't glow and the board refuse to boot. I freshly installed Raspbian Buster but it didn't change anything.
Then I used a usb drive for booting just in case my memory card is corrupted(installed Raspbian buster on usb drive), but still nothing good(I didn't change OTP as I am using Pi 3 b+ here). So, clearly corrupted memory card is not the problem here.
I then used my multimeter to check continuity and voltage, to check if led was broken or USBs don't work, but still everything is continuous and all USBs are working fine. Power supply is legit too.
I don't think that the board is defective as I didn't tweaked anything and even multimeter shows some areas(where I tested) are working fine.
Can anyone suggest the solution to this or any troubleshooting options?
UPDATE I will keep my PI in freezer for some days just to try it for a last time. I will get back to the solution then(if any).