The best way to make sure you have the right bootloader is of course to program it yourself. If the issue persists after flashing the right bootloader (or you can't flash the bootloader), the next suspect would be baudrate mismatch. You will have to check the following settings:

• the right target board is selected in IDE settings
• the XTAL clock matches what you really have on your board (many Arduino clones are mostly compatible with original except for quartz frequency)
• the baud rate for uploading your software (upload.speed parameter in board.txt) matches whatever bootloader you have (if you can't reflash the bootloader, you may want try several values and see which one works. Default is usually 19200).

Note that there'a great site https://arduino.stackexchange.com/ where Arduino experts hang out, so in the future you may want to ask your Arduino-specific questions there.

The best way to make sure you have the right bootloader is of course to program it yourself. If the issue persists after flashing the right bootloader (or you can't flash the bootloader), the next suspect would be baudrate mismatch. You will have to check the following settings:

• the right target board is selected in IDE settings
• the XTAL clock (f_cpu paramter in board.txt) matches what you really have on your board (many Arduino clones are mostly compatible with original except for quartz frequency)
• the baud rate for uploading your software (upload.speed parameter in board.txt) matches whatever bootloader you have (if you can't reflash the bootloader, you may want try several values and see which one works. Default is usually 19200).

Note that there'a great site https://arduino.stackexchange.com/ where Arduino experts hang out, so in the future you may want to ask your Arduino-specific questions there.