Attempting to install almost any program while your virus detection program is "turned on" may give a warning that can look like it's telling you about a virus. What it really means that something "suspicious" is going on - like writing new information to registry and other critical files. (Note that if this happens, the antivirus may have blocked the installation - and you may have an incomplete installation that needs to be fixed.)

Once the file is downloaded, you need to open your virus scanner and scan the downloaded file before you begin the installation - if you're worried about where it came from.

The above step is usually overkill, since your antivirus should check all incoming stuff during the download operation.

If it doesn't find a virus in the downloaded file, you may need to turn of the virus scanner while you do the installation.

Don't forget to turn the antivirus program back on when you finish the install.

John