现在电脑只要打网页或者文件就会出现 System error!
Your computer was infected by unknown trojan
It's dangerous for your system(critical files can be lost)!

Click OK to download the antispyware program to clean your system!(Recommended)

点OK就会到一个网址下载SETUP.exe 点取消才算过关。瑞星现在查不出病毒，我该怎么办？


[用户系统信息]Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 2.0.50727)

谁给出个注意，弹的我快崩溃了…… 手指头都点困了。