system on it's own shuts down

first, running windows 7 ultimate 64 bit on a sony vaio VGC-JS230J desktop. Haven't any problems with the computer since new 2 years or so. Recently noticed it would turn itself off but i could restart with no issues. This would usually happen as i was using the scroll wheel on the mouse. This morning it shut itself down and on restart, first kept looping automatically to shutting down, then brought up a repair screen when i started in safe mode. it went to "self repair" mode, but using the repair disc didn't help and after that would only restart and fully load windows if i rebooted using the EaseUS backup utility disc (i have a full clone of the harddrive. I have everthing double backed up, back up -both as data backup and a disc clone so i'm not worried about rebuilding or re-installing every program on the computer - would just prefer not to have to all that. Any suggestions of what to look at?

 

should have added, when system restarts on it's own and goes to system recovery options, it shows the following msg "File: \windows\system32\winload.exe status: 0xc000000e info: The selected entry could not be found because the application is missing or corrupt" 2nd - a number of keys, like the entry key for carriage return do not work normal, if i try to use it, it just drops the whole paragraph i've been typing down and not giving me a new line to start a new paragraph