Internet constantly drops out on one computer?

[Nemozzz]

Hello,
So on my desktop computer, the Internet keeps dropping out and saying "connected, no internet" which means that I cannot do anything online - very annoying.
I have a sky SR102 router and a custom built PC which has worked pretty much absolutely fine for the last couple of years however just the other day it started randomly cutting out and I have no idea why.
Both wired and wireless are doing this however all the other devices are working on this network so it should just be the computer (except for a wireless extender we have where it only ever says no internet and nothing can connect to it).
I am currently performing a full system scan but I doubt it should be viruses (any things possible though I guess).
Does anyone know what could possibly be happening?
Thanks!

 

[Zothik]

You internet adapter on the mobo might have started to fail. That's what it sounds like to me at least. If you have a PCI-E internet adapter, try mounting that in your mobo and run your internet through that instead.