Laptop won't boot. Me has tried everything.

Hi hoping for help from some experts here...

MY laptop isn't booting, screen remains blank. Long story short after trying everything I think I can conclude that there is something wrong with my mobo/cpu. Earlier I was convinced its a ram issue, but a brand new ram didn't fix my problem..

My question to the experts is what cld I possibly do to fix my mobo.

I don't believe its fried, coz it stopped booting merely after a restart. and I can here my hdd spin silently.

What are the various problmes(fixable) that cld happen in a motherboard/cpu that cld prevent a pc from booting?

Previously I had a similar problem (lappy would start but wld randomy hang), it got fixed simply by 'cleaning' the mobo . HOw and why would somthing like that happens?

Thanks