1. Always back up your important data.
2. Always shut down your computer properly, never just switch off the power. Often you will get away with it, but if the computer is in the middle of writing to the hard disk you may cause a severe problem.
3. Always make sure you are running anti-virus software and that it is up to date. This need not be expensive. Free programs such as AVG work very well. Microsoft Defender is also free and will help to protect your computer and its data.
4. Make sure you are using a firewall, at the very least the one provided within Windows.
5. Avoid the darker side of the Internet. These are the places that you are most likely to pick up rogue programs, Trojans and viruses.
6. If you computer starts to behave strangely, slows down dramatically or makes new noises (particularly the hard disk) take immediate actions to have it looked at. Don't wait for things to get worse or you could end up with a total failure.
7. If you are plagued by annoying pop-ups this could mean that your computer is infected by a virus.
8. If your computer does have a problem, try to remember if this coincided with something else, such as a new program being installed. This will be a great help to anyone trying to fix your computer.