I want to teplace the motherboard

Okay so frequently when I power on my machine it shows the booting up page and ending machine will stay for like 1 hour no 30 minutes before tripping off and then restarts again by itself at first we thought it was the same cmos battery because he kept displaying an error message on this screen saying that the cmos battery is exhausted we changed that we change the cmos battery but the um problem continueed so we call the technician he looked at the motherboard and said the motherboard has some swollen capacitors which we change we changed so after he changed it he brought the motherboard back and the problem continueed and right now he ischecking the RAM and he told us to look for another alternative in getting the motherboard