Then your computer must be infected with malicious software. Go to hao 123 website to download a malware cleaning assistant and clean it up. If you can't clean it, when you try to enter the system, press F8 to enter safe mode.
You can also get a super rabbit in the common software of hao 123 to clean the system.
Another way is to download 360 security guards to clean up malware.
These solutions to your problem should be no problem.