|emachines systems have a reputation of using el-cheapo power supplies in their systems that tend to malfunction and fail a lot more often than average, and when they DO fail, they are a lot more likely than average to damage something else while failing, often the mboard. This is especially likely if the make of the PS is BESTEC.|
There was a successful class action suit against emachines in the US not all that long ago regarding problems mostly caused by those el-cheapo power supplies!
If the original PS is a BESTEC, it's quite likely it damaged the mboard, and/or the video adapter! That may have been what damaged the original mboard in the first place!
Failing power supplies are common and can cause your symptoms.
Check your PS.
See response 4 in this: