Arduino Pro mini not responding to uploading sketches

hello i have a small problem all of the sudden one of my pro mini board stop working i can't even upload a simple blink sketch. I thought it was the FTDI adapter and it wasn't i tired another Pro mini and it worked with no problem. Only thing i can think of maybe the Bootloader got messed up sense i do not know how to program a bootloader i tried to search google there are a lot of ways some tell you to put this wire on this pin some say use a iscp or icsp programer and some say do it from one arduino to another. The thing is i do not know how and i do not have a iscp/icsp programer. is there a easy way or a site i can look at that gives me the steps on how i can do it with what i got? i have 1 ftdi adapter i have 1 mega board and i have 3 pro mini boards can someone please help me out?

Thank you.

Even bootloader crashed you get error. What error you get when you try to upload blink program.\

If you confirm bootloader is crashed , Use avr pocket programmer it simple way of programming.

I have given up on pro minis because of the flaky uploading process.

Hello thank you for you for responding back the error i get is

Binary sketch size: 1,084 bytes (of a 30,720 byte maximum)
avrdude: stk500_getsync(): not in sync: resp=0x00

I never had a problem with the pro mini into now. Last night was working good i was updating some sketch i been working on And this morning i went to plug it in and i get that error message. i connected another pro mini and that works with no problem.

Yes its bootloader issue . just use avr pocker program for uploading bootloader

i Fix the bootloader on it now it’s working once again looks like that is the problem thank you.