Computer Problems

This is the second time that my laptop has crashed in the last two months. I notice that my computer was having problems connecting to the Internet and moving slow. The only new program that I had on my laptop was Mozilla FireFox browser. When I uninstalled the program my laptop would boot up but all the programs wouldn't finish uploading. I did a series of things that I thought would help with the problem. Then I received a pop up message from my antivirus software saying that a Trojan was on my computer and Norton was unable to get rid of the Trojan. I don't know what happen but my antivirus software was wiped out. I signed up for a free trial with Norton so that I could get the Trojan off of my computer. Unfortunately, I had to reinstall windows and I'm still installing some programs back on my laptop. I was unable to use my laptop for three days. Now I'm I'm the market for some new software but I'm thinking about changing from Norton. I heard some mixed reviews about Norton and was satisfied with it for the last two years.