Dell Inspirion 2020 won't start

Help! We have a Windows 8 Dell Inspirion 2020 that started not loading yesterday. At one point I was able to log in and had Norton run power eraser and found no threats. It did say to update Java, as it could be a security issue. I tried and it went to restarting and never stopped and never restarted. Initially after Norton helped all the icons came back and I was able to use everything. Then I tried the Java and it would not restart. Today it would not open again and after a few hours I was able to get to the refresh and update area and followed the instructions again it shut down. When I turned it on again a blue bar scanned under the Dell logo and it said F12 for boot options and again went to the black screen and shut down after about 20 min. Can you help please?