Sounds like it died. Is it all settled down now? (no power, no smoke)
Since it's an eMac, I presume it is out of warranty or Applecare.
Do you have an Apple Retail Store or Service Provider close by you can take it to and have it looked at?
Of course you could contact Apple Directly
Your screen, since it shows no video and was smoking, has most likely blown. Since it is a CRT monitor, it cannot be replaced by Apple, as they have discontinued the CRT display. You will most likely have to purchase a new computer, as eMacs are now considered obsolete.