Guys, I came to a sad realization. Seems like RTL8201 is not a very good solution in Mac. I sincerely thank guys who wrote the kext for it. I really appreciate your work. However, RTL8201 is a 'piece of shit' lan adaptor used in 'piece of shit' cheap mobos like mine... So i finally sacrificed a PCI slot for a D-Link PCI Lan adaptor which works seemlessly with Vista and Mac. Problem bypassed! (Not solved). Anyway, i learnt a lot by trying to make it work so i have no regrets.

For onboard VGA with only 1024x768 res. like my NVidia GeForce 6100 in NForce 405, there is no working kext yet... I highly doubt that there will be ever since there are very few cheap-ass fellows like me who will suffer and have the need So i'm intending to upgrade my onboard VGA to a PCIe VGA later if i have some extra cash. Till then, i'll be ok with this default settings...

Thanks all the guys who tried to help me... Thanks a lot!