回複：ppzcgg please help

ppzcgg and all,
My IE tools -> internet options ->security -> Internet -> "sites", "custom level" and "default level" were disabled by virus or spyware. It was set on "High" and I can not change it. Could you please tell me how to enable them? I looked into registry but don't know which key to change.
Second problem, I can not download any sofeware from internet. The IE will go blank and then a small icon appears on upper-left corner. Does it have something to do with "High" level security set by virus?

Thanks a lot!