So recently, I've been experiencing problems on my Macbook Pro. I got it in early July 2014, and I didn't have any problems with it until not too long ago. Sometimes, when I'm typing, it will lag, and then whatever I was typing will appear after about 3 seconds of lagging. I ran a full scan on Avast!, and it did not detect any infections, however, it was unable to scan 157 files, but it successfully scanned nearly 650,000 files. On Friday, I accidentally downloaded the browser hijacker "Installmac," when I thought I was downloading Skype. I then downloaded Avast!, and then I used it to delete the brower hijacker's files. There is none left. I've tried restarting, but it has not solved the problem. What is the problem? What should I do? ---------- Adding on, the screen freezes/lags as well! As stated before, it is only for 3 seconds, but I would rather have it not freeze/lag at all.