In order to effectively remove spyware that has infected your computer, you will typically need to download and use an antivirus or malware removal program. These types of programs may be free to download and use, or you may need to pay money to license the program and effectively purge your computer of malicious software. You should follow any instructions provided by these programs for scanning your computer and removing spyware; most programs are quite easy to use. To remove spyware that is especially malicious or difficult to remove, however, you may need to run the program in safe mode or after booting from disk, or even reformat your hard drive.
Spyware is a program, typically considered malicious, which monitors activity on a computer and then uses information entered into the computer for a variety of purposes. These uses can be relatively benign, such as to transfer information about your favorite sites to a company that then creates popup advertisements on your computer for similar sites. There are also more malicious uses of such spyware, such as with keylogging software that monitors your actions to steal passwords to bank accounts and other sensitive information.
To remove spyware, you will typically need to use a program specifically developed for use in malware removal. This can include a good antivirus program, though there are also programs created for use with spyware exclusively. You will want to ensure that the program is safe to install, since some viruses and malware are spread through corrupted program downloads and then update the program to its most recent version. Assuming you are able to do all of this, you can then remove spyware from your system by running a scan of your computer using this software, which should identify the spyware on your computer and allow you to remove it.
Some spyware can be fairly difficult to remove, however, and you may need to try a few different options. Spyware programs can sometimes prevent you from running an antivirus program properly, so you may need to start your computer in an unusual way to avoid this issue. You may need to start your computer in safe mode — how you do this depends on your operating system (OS) — or boot your computer from a clean install disk.
Both of these methods can allow you to avoid any control over your system a piece of spyware may have. If you are otherwise unable to remove the malware on your computer, you might consider reformatting your hard drive. This should typically be done, however, only if you have all of your important data and programs backed up and have tried all other methods to remove spyware from your system.