Some extra precautions to take.
Make sure you have backup copies of ALL your personal files on an external hard drive. Preferably one that is NOT plugged in to your PC so it does not get encrypted.
A spare copy of your important personal files on CD or DVD would also be useful (good idea to have important files backed up in at least two places).
If you have more than one PC in the house, copy personal files onto the other PC as a spare or backup.
Consider reducing the number of personal files you have on your PC to a minimum. I have most of my personal files on external hard drive and work with them from there. I have almost no personal files on my PC, just Windows and a couple of personal files.
Consider using software to make an "image" of your hard disk. I have an image of my Windows files stored on an external hard drive. If I need to "reinstall" Windows I can do it in less than 10 minutes.
There are a number of programs you can use to make an image of your hard disk. I use Macrium Reflect Free Edition, which as it says, is free, and has been excellent for me for making images of my hard disk. I have done numerous restores from these images and it works every time.
There are other products like Acronis True Image and so on.
DONT assume this Cryptolocker will not happen to you, it can happen to anyone.
Even if it does not happen, taking precautions like I have listed above may save you losing important personal files.