If you're asking the question, you possibly have it. However, there are some good signs:
- You have too many popup windows. Some of these are a normal part of web browsing. But if you get popups before you open your web browser, it's a sure sign you have spyware.
- You can't reach certain web pages.
- Your home page has changed and you can't change it back.
- Software other than your regular antivirus warns you that you have spyware.
- You get an antivirus message warning about multiple infections. Most antivirus software will give you a warning for each virus it detects. If there's a second virus (unusual), it will give a second warning. It will rarely give a single warning of multiple problems at once. However, spyware sometimes does this in order to trick you into downloading it.
- Your web browser has new toolbars you didn't remember installing. Toolbars come with a lot of software (Yahoo, Ask.com, Google), but if one appears for something else, and you haven't installed software recently, it's a warning sign.
- Your computer runs slowly. This can be caused if the computer is low on memory, but if you have a new computer, one cause of the slowdown can be spyware.
If you have any of these issues, it's a good idea to download and run Malwarebytes to scan for problems.