|emachines computers are well known to have el-cheapo power supplies that tend to fail more often than average, and when the power supply fails completely, they are a lot more likely than average to damage something else, often the mboard.|
This is especially the case if it's a BESTEC power supply!!
If you have not been fiddling inside the computer case just before this happened and have not changed the ram installed in it, it is very likely that if you replace the power supply BEFORE it fails completely, doing that will restore your system to working again.
Unplug the cord to the computer, or otherwise switch off the AC power to it, open up the computer case, and find the label on the power supply - if the brand is BESTEC I advise you, if you find ANY indication the power supply might be in the process of failing, DO NOT trying booting the computer anymore - if the PS fails completely there is a strong likelyhood it will trash your mboard!!!!\
Failing power supplies are common and can cause your symptoms.
They often partially work, fans and hard drives may spin, leds may come on, yet you may get no video and the mboard will not boot all the way.
Check your PS.
See response 4 in this:
"...The tower use to get hot ..."
It should not get hot! That may be an indication the fan in the power supply is spinning too slowly or has stopped spinning because of wear producing too much friction in it's bearings.
DO NOT replace the power supply with another BESTEC one!
In most cases you can replace it with a standard sized standard ATX power supply.
Standard (PS/2) power supply size - 86mm high, 150mm wide, 140mm deep, or 3 3/8" h x 5 7/8" w x 5 1/2" d , or very close to that, though the depth can be more or less for some PSs.
Don't buy an el-cheapo PS.
See response 3 in this:
Your power supply must have at least the minimum capacity required to support a system with the graphics card you are using installed, or the max graphics card you might install in the future.
(Onboard video - video built into the mboard - IS NOT A CARD!)
You can go to the video card maker's web site and look up the specs for the model - often under system requirements - the minimum PS wattage, and, more important, the minimum amperage the PS must supply at 12v is stated. If you don't find that, any card with the same video chipset including any letters after the model number has very similar minimum PS requirements.