Trendmicro Internet Security 2007 blocks internet when trying to install on Dell Optiplex, help?

I have tried 2 times to install this security system on my computer but it blocks my IP address so I have to take it back out of computer to use internet. Technical support at Trendmicro is of NO help. Can anyone offer suggestions on how I can use this software in my computer?

Trendmicro Internet Security 2007 blocks internet when trying to install on Dell Optiplex, help?virus protection

I wouldn't use Trendmicro at all. They want you to pay them. I have used AVG Free version for a number of years. It's free to download, it updates for free, and it doesn't slow your system down. It doesn't cause problems like that, either.

I don't work for them, by the way...