Recently, my MacBook Air has been experiencing issues when trying to download things. The most common problem is downloads that stop frequently with the error in the Safari download manager that the "Network connection has been lost." I thought maybe it had to do with my local router but then I have been experiencing it at a friend's house as well so there goes that theory. Could malware of some kind be to blame? How do I best check for it or otherwise fix the problem? Could the wireless card on my computer be faulty?