If you have never experienced a virus on your PC, you are very lucky. Viruses will often render a PC a virtual vegetable. Performance is terrible, you cannot connect to the Internet, applications don’t work and your data is at risk of being corrupted or lost. As I have mentioned in this forum in the past, you should always have a back-up copy of your user data on some external media just in case. It is not just hardware malfunctions that can corrupt or destroy your data, viruses can do the same.
Consider yourself on notice. If your antivirus application is not up-to-date, you WILL get an infection and the cost in terms of lost productivity, data corruption and virus removal will far exceed the cost of the application. Do yourself a favor the keep all your applications up to date, especially those that protect the security of your PC.
Thats all for now, here's wishing you a good boot!