Reprogramming my arduinos

Hi All,
And many thanks for your input! After a lot of head rattling, scraching and Coffee, it began to come back to me, Yes all my Arduinos are working and programmable via the USBasp programmer, and I even have a Maga2560? that will take the usual USB connection.

If I try to download the bootloader I get an error, is it part of the standard install? Perhaps not, as I suppose there's different ones for different boards! Still I can work without the bootloader and save a few bytes!