NOTHING happens. Any suggestions?Disconnect everything except the video card,CPU and fan, one stick of RAM, the mouse and keyboard and the monitor.
Anything now ?I dont have any extras connected.. still nothing, CPU???I have a similar problem with my 4 year old emachine.It was getting weird slow so I upgraded to the newer firefox and it seemed fast.So then I downloaded a free microsoft antivirus and the next morning It would not power up.I am getting a green led on mother board and no other signs of life.HELP!!It is an emachines with windows xp .WELL it could be either the CPU or the board...unfortunately other than a shop there is no easy way to find this out without both another similar board and CPU.Would the LED light still light up, if the motherboard didnt work? The processor is a Celeron D.. 4 years old.. i think it was toast.. do you think i could find another Celeron D.. i dont know the spec to the mother board so i can find out what it supports.....Yes.
An LED needs very little power to glow green and is no INDICATOR of either the MBoard's or the CPU's relative health...hmmm well should i just get a Celeron D processor.. they should be cheap now.. try it.. and if it doenst work.. well its the mother board.. and where can i find THAT replacement....Personally i would start putting together a wish list and start saving up to BUILD a new system...
Since you aren't replacing everything you could probably do it pretty reasonably.
Decide on a budget and go from there...

BTW Good Luck in the Rose Bowl !Rose Bowl? I never watch that.. I don't watch college sports.. Why is Patriot a team name?

So just save up for a new system??? And how can i get my old information and PROGRAMS back from the other computer.. like programs we bought?The programs you bought should be on the CDs you installed them with.

As for data on the hard drive, you could do one of two things:

1) Once you get the new computer, physically remove the old hard drive from the old computer and install it in the new one.  Copy data from old drive to new drive.

2) Remove old drive from old computer and put it in one of these doohickeys:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817145656

Plug power in, connect USB cable to new computer, and voila!