And just to add to Jim's point, you'll find system restore on start, all programs, accessories. Click on system restore (it may be under yet another folder called system tools) and there should be an option to create a system restore point.
There are lots of disk image softwares available which make an exact copy of your system which you can use at a later date. Try this:
http://download.cnet.com/Macrium-Reflect-Free/3000-2242_4-10845728.html?part=dl-&subj=dl&tag=button . It's called Macrium Reflect Free Edition. Download it and then run the installer. Once it's installed: create a Linux Rescue CD (an option in the program) and then create a backup image on DVDs. It might take up quite a few DVDs but it's worth it. It will then be a backup of all your settings, prgrams and personal documents.
It's also worth backing up your personal documents on an external drive (or try Google Drive - free cloud storage for up to 5gb) - just in case Macrium doesn't work for some reason if the cruical time comes.
It's always worth having a Macrium backup - before your computer starts going wrong.
Swallow - I haven't backed up for a while! . If the time comes, enter the Linux Rescue CD , and when the boot screen comes up (giving the brand of computer) it will give a button you should press to bring up boot menu. You can then set to boot off the disk drive. It will then boot into a portable system which should help you and give instructions on how to proceed. Macrium when you're creating the DVDs should also tell you this, or something else.
Remember to write all this down because when your computer goes wrong, you can't go onto Rootschat from that machine.Before you run Macrium, make sure to do a virus scan, either using MalwareBytes as jc26red suggests or Trend Micro Housecall (
http://housecall.trendmicro.com/uk/). Because if you don't you could be backing up a virus. If they find anyhting, delete the files and also write down the name of the virus and tell us so we can see if you've found the culprit.
HD Tune Free Edition (click here to download:
http://www.hdtune.com/files/hdtune_255.exe ) will be able to run a scan of your hard drive to see if there are any errors. Therefore you will know if you have a hard drive soon to fail or not.
I know I have put a lot and so have Jim and Jenny, so remember you can ask us if you need things to be explained again. Don't be

with all this information - I know it might be a bit overwhelming.
Any excuse to use a smiley! Though these Christmassy ones are getting on my nerves a bit nowJack