The downloaded file(s) do not have a virus in them.
Tell your anti virus software to ignore the warning.
If Windows smartscreen tries to block download click on "more info" then click on "Run anyway"
Download method using self extractor
Click here if using Windows XP and download .net framework first
1/ Click here to download PCBCAD51 exe file.
2/ Click on 'Save' then after downloaded click on 'Run'.
3/ Click 'yes' for user account control if asked.
4/ Click on 'setup'.
If you have any problems let me know.