I wasn't implying you buy a new laptop, but rather use Linux (which is free) and doesn't have a problem with viruses, but I didn't state explicitly that you should use Linux because I don't really care what you use. But about the ads, that was a genuine warning because viruses have been found in ads on reputable sites, so if you insist on using an insecure OS you should at least use an ad blocker for your own protection. I don't consider Flash to be secure either and personally consider it a good idea to use something like FlashBlock so Flash only runs when you permit it, this will go some way to increasing your safety, but an ad blocker should catch most Flash ads anyway. I am also curious as to which browser you are using since I still hold the belief the IE is still poor security-wise, but I hold no delusions that the others are perfect and immune.