40 ways to fix your PC before you call an expert (5)

5. On-demand scans

A whole bundle of problems are caused by viruses and spyware, from slow performance to unexplained reboots. It goes without saying that you should keep your anti-virus and anti-spyware tools right up to date, but you might want to run an on-demand scanner as well to get another opinion -- Spybot Search & Destroy and Microsoft's own Safety Scanner are two good choices that won't interfere with your existing security tools.