My personal computer is down :(

The illness my computer contracted when I tried to do a system update about a fortnight ago is more serious than I thought. At first I thought it was only the power supply unit (PSU) that had fried. Now it seems that my motherboard is affected. It fails to power up even after I put in a new PSU. So I guess there's nothing more I can do except to get a new PC. Should I build a new one with whatever parts I can salvage or should I buy a full system off the shelf? The Eee PC from Asus looks tempting since I mainly use my computer at home for emailing and surfing the Net. Any heavy-duty stuff like programming I can make use of my notebook from work (though I don't bring it home everyday).