回复：小女子求教大侠：务必帮忙看看，参谋参谋。。谢谢。

I had a similar problem for E-machine 1840 and it was found out to be the motherboard problem. I brought a motherboard from Fry for about $70. After changing a new motherboard the computer works again. Generally speaking, Fry allow to return the motherboard within 14 days without charging the restock fee even if changing the new motherboard does not work for your computer. E-machine charged about $160 for the motherboard. Ask a friend to have a basic computer knowledge for help.