Primex

Seriously, I reformatted my laptop about 6 months ago. For some reason now the computer freezes up and goes slow. Just saving a file took 5 minutes and took up all the CPU. Then suddenly I got the blue screen of death. No one could help me and someone said that I needed to reformat it again. So I did. Then after about a week, the same thing happened after about 5 days. Now it's like it won't stop doing that. It'll work perfectly for about 5-7 days, then for some reason it just does it again. Sometimes I'll get the blue screen of death after just a couple days. I thought I was downloading a virus or something, so I decided to experiment and not connect to my router and not go online at all, but it still did it after 5 days. What's the deal here? Does this happen to computers? I'm going nuts here.