No, you can fix it if you find out what is wrong.
You test by substitution or elimination.
I forgot to mention, replace the CMOS cell.
Next, check the BIOS and see if the settings are correct.
Try a good power supply to see if it makes a difference.
Also try to start up with no hard drive.
And remove the DVD drive. Maybe it is failing.
Check the contacts of the RAM modules.
Even try no RAM and see what it does. It should start and turn on the beeper.
Above are the things most techs would do anyway.
Replacing the Motherboard is a last choice because of cost and time.And you might harm a new motherboard if thee was some other kind of problem.