OUCH I'm reallllly sorry to hear that your mother board went out...
especially because I have the Brother PC6000 also.
Did something happen, like other suggest, with electric current?
I don't think mine is 12 years old and it would be a tough decision if I had to make one but I think I'd just get a new machine for the $400. I'm betting there are a lot of machines on the market NOW that are similar to the PC6000 for about the $400...which is no where near what I paid for it new!
I'll hug my machine and talk nice when I sew the next time! LOL