A big problem with the internet lately is spyware and I have been frequently called out by my friends and family to fix problems with their computer caused by spyware.  Spyware basically consists of files or programs installed on your computer without your knowledge or consent.  These programs then do certain things, for example monitor the websites you visit, and then display popups based on your internet browsing habits.  For example, if you visit mobile phone websites, you may get mobile phone popups.

One of my friends was hit by this pretty hard.  As soon as he opened up Internet Explorer he had 12 popup windows open trying to sell him everything from mobile phones to Viagra. 

Fortunately it is possible to remove spyware, using programs such as Lavasofts Ad-Aware which is a free download from here.

All you need to do is download it (the free version is simply called Ad-Aware. The versions you have to pay for are called Ad-Aware Plus or Ad-Aware Professional).  Once you've downloaded it, you can perform a system scan and remove any objects it finds. The program should be simple enough to operate.