Back up, I recommend Norton Ghost.
Security, I recommend Online Armor++, but it's a pay to play for the full versinon.
It goes without saying,
Agree!
BACK UP DATA that is important to you. I back up my data to a D:\ partition AND to at least one USB exernal drive.
[I learned the hard way, when I has a system crash a few years ago and lost years of personal data.]
External (USB) drives are cheap. BUY one and USE it. Flash drives are from about 256mb to 64gb. A 4gb flash drive costs about $8.00.
Never put important data exclusively on your start-up/OS drive (usually Drive: C:\). Create a partition and put data contents there. AND back it up to DVD-RW AND/or external USB drive.
Use a drive imager program occasionally. That will save having to re-install from scratch and re-set an OS drive.
[I have an OS partition of about 30 gb and I occasionally use CloneGenius to create an image file. That has saved me many hours of reinstall time when I have had to restore the image files.]
Get in the habit of backing up important data. Get a back up program and use it. Otherwise, one day you will lose it. One day your drive will fail or your computer will quit.