Be very careful about what sites you visit. I found out the hard way that there are a lot of copy cat sites on Google and if you click on them they will launch a slew of problems for you.
I was comparison shopping for flea pills and HeartGuard for my puppers and I thought I was getting on PetMeds.com and it was not their site. This thing sent all sorts of crud on my new laptop and I didnt find out until this morning when it would not boot up right. I had to go into the thing in safe mode and reset it to a day that I new it was running great.
I pride myself on having a bullet proof computer but I think I met my match yesterday. So I ended up spending all day today cleaning my wifes computer out and working on mine and getting both of them back to being "Hack Proof". I have lots of rare documents and information on vintage sewing machines on here and if I could not get back into it they would be all gone forever. :(
And lots of the stuff I have on here, I am the only person on the planet that has the information. So Sunday I am running a back up DVD so I will never loose any of it.