When you open your Web browser, you don’t see your homepage, but some random advertisement site and several ad windows pop up, leading you to other web sites you probably don’t want to see. If you try to open a new Web site, it may be blocked and more ads pop up.

This means that your browser has been “hijacked” by spyware which has installed ad-links on your PC. They are activated when you open your browser and visit any Web page. Another cause could be a virus. In any case, you need to remove this threat.

First of all, clean your browser history, cookies and temporary Internet files. In Internet Explorer, you can do this by selecting Tools, Internet Options and it should all be in the General tab. Also, make sure all other options are set to default, such as Security and Privacy settings.

If you have a spyware cleaning program, make sure it’s up to date and scan your hard drive. If you don’t have it, download CCleaner, Ad-Aware and Spybot Search & Destroy and scan your PC. This can remove some or all of the spyware. If you have problems running these programs, go into Safe Mode (restart the PC, press F8 and hold it until you see the menu where Safe Mode is displayed as a start up choice) and run them from there. Repeat this with antivirus programs.

There are also special programs that deal with hijacked browsers. You can test Hijack This, Browser Hijack Retaliator (no support for Windows Vista) and Browser Hijack Recover. My experience with these programs has been mixed, but they can help you if you use them correctly.

You can also use the System Configuration Utility (msconfig) to stop spyware programs loading at startup. Click here to read how.

If you don’t succeed with the methods described above, go to Windows Live OneCare Web page and use their free online scanner. It has helped me on many occasions and it may remove all your threats.

Unfortunately, sometimes all these programs and methods fail and you are left with only one option: System Restore - It saved me several times, when I just didn’t know what else to do. Just go to Start, All Programs, Accessories, System Tools and select System Restore. Next, choose a date when you think the PC worked without problems. Proceed with the next steps and after the next reboot, the PC should be back to normal. You have already cleaned all spyware and viruses and all settings should be back to normal as well.