might or might not

I was thnking about thisa couple of days now I might download some vids from the site nd make amvs again but I'm worried that it might cause problems since it turned out that the reason why our old computer which we got back put nothing was saved had lots of viruses was because someone did not know what they were doing when they were downloading its either me or my sisters and I'm looking at my older sister because a little bit after she downloaded angels online the problems occured but it could've been problems from me downloading stuff wrong to (I'm not really good with downloading or anything computer related) so when my mom is with me I might try to download some of the vids but only by her permission and by her watch (maybe) or I write down the instruction again on downloading the vids
again we're not sure what caused our old computer to get viruses it could've been me or my sisters fault for our downloading stuff to much