I have spyware doctor installed and registered on my computer. Yet windows defender has repeatedly popped up and taken over my computer disabling not only spyware doctor but also every other program on the computer. I have to do manual restores just to delete the program. Also when it takes over the system it starts up the internet automatically and brings up all kinds of advertisments. How can this program be stopped. All my security and firewall settings are set high. Yet Windows allows it in because it carries the microsoft certificate.1 person got this answerI do too

This does not sound like Microsoft's Windows Defender. It sounds like your computer is infected, probably with a rogue security program. The real Microsoft Windows Defender is not part of Windows XP. Your system is infected with a rogue antivirus program. It is called "rogue" because it pretends to be A Good Guy but is really Evil. Do not pay them! Look for removal steps here Bleeping Computer removal how-to's - http://www.bleepingcomputer.com/forums/forum55.html or here - Malwarebytes malware removal guides - http://tinyurl.com/5xrpft Malwarebytes' Anti-malware (MBAM) or SuperAntiSpyware will often do the job. Both have free versions and you do not need to purchase these programs. These may work for you and all may be well. However, in many cases the computer will also be infected with other trojans and protected by a rootkit. These machines are extremely difficult to clean. If your machine is one of these cases, either get guided help at one of the specialty forums listed at the link below OR take your machine to a local computer professional OR back up your data and do a clean install of Windows. It is your choice. I don't recommend using BigComputerStore/GeekSquad types of places. http://www.elephantboycomputers.com/page2.html#HJT-linksMS-MVP - Elephant Boy Computers - Don't Panic!