have an emachine t6420 about 3 years old that is giving me an error message as soon as it boot ups that windows is shutting down due to serious error being detected. new to repairing computers, trying to repair myself but not sure what it could be. the only way to work on it is in safe mode, i have scanned for viruses, performed disk cleanup, had defraged a week or so before this started. trying to get a system recovery disk now, no telling how long that will take. any ideas would be appreciated.