Hello. I have had my MacBook air for a few years. Currently running OS Sierra. 10.12.2 i5 with 4gb ram. My system has spyware or something on it. It acts like it is taking up more power and resources then necessary, and I am just browsing the web most of the time. Safari runs great after I restart but after a few hours, it starts to bog down and lag. Considering the specs of this computer and how new it is, this is unacceptable. The computer right now reminds me a bit of when I had Windows XP and had viruses and spyware all of the time. I take responsibility for some of this. I was on a site and they let you download the videos in .mp4 format. During the process, a lot of popups will open and possibly install spyware. I never downloaded anything other than the .mp4 file. Is there a possibility that the virus can piggyback on the .mp4 file? If so, do I need to delete my stash of .mp4 files from my external hard drive too? I also use an online forum for downloading electronic music and I get a lot of popups, new tabs, and automatic downloads from there. I never open the files it downloads and always put it in the trash can immediately. I know I have spyware because I get the "adchoice" **** that shows pictures and shopping I have already looked at. I HATE THAT. It is such an invasion of privacy and I know something is wrong. I almost system restored, but I thought "man, I had to do this all of the time on windows but I should not have to do it on a mac".. Again, a lot of this is my fault and I made a pact to not download anything else unless I pay for it. I'm sure I am not alone in this mistake, but whatever. I need some recommendations for the BEST virus programs that will actually find the spyware and viruses, and delete it. I know a lot of virus software out there is just another scam, and finds "viruses" and "deletes" them to look like it is working, but never fixes the problem. I currently have avast, dr cleaner, and ABP pop up blocker. They obviously aren't doing the job though because something is wrong. They're just free programs, anyway. I also need something to clear out my disk space, get rid of duplicates, and find worthless junk thats taking up a crapload of space. I'm willing to spend $20 or $30 bucks. Sorry for the long post but I am desperate. Thank you so much.