I want to know in that sites I can find courses of Repair of
motherboards in any language.

If you mean actual physical repair of motherboards rather than
flashing or battery change -- not a chance. Identifying hardware
faults is simply not possible without manufacturers diagnostics, a
heck of a lot of equipment and a great deal of knowledge. Yes on
occasion I have repaired motherboards when it has been something
discrete, but no sane person would attempt it :-)

These people would seem to differ in opinion....

http://www.monitor-repair.com/motherboard_repair_course

..... but it?s going to be (what I would consider) low level stuff.
Sorry for being so negative.

Best