Microsoft has shipped its final update for Windows XP, which means all the new security holes will not be patched. Nobody knows what will happen next, but malware writers are expected to target the remaining machines. If you are still running Windows XP, it would be a good idea to make it as secure as possible. Unfortunately, there is no "magic bullet". The things you can do to protect XP apply to all versions of Windows. However, because XP will now get more insecure every month, you need to take protection much more seriously. It's a huge problem. There are roughly 1.5 billion PCs in the world, and NetMarketShare reckons that 27.7% are still running XP. That's more than 400 million machines. Since XP is fundamentally much less secure than Windows 7 (48.8%), Windows 8 (11.3%) or even Vista (3.0%), it's a very attractive target for malware writers.