my e machines w5243 desktop when it turn it on it goes back off and i will have to keep turn it on and it will have a message window error recovery and option to start in safe mode and them it will go back off
Make sure your HDD are properly connected, try booting into safe mode.
If that doesn't work, Boot to a windows Disk and select repair, (The disk doesn't have to be the exact disk that was used to install the first time, but it does have to be the same version).