There is a lot of great software on the internet and whatever application or utility you need, you will probably find it with a search using Google, Bing or one of the other search engines. Among the tens of thousands of good programs are a very small number of bad ones.
The chances of coming across a bad one are small, but just in case, Windows 8 has a technology called SmartScreen that tries to protect you from bad software. If you download a program from the internet and then try to run it, Windows 8 will block it if it does not recognise it using SmartScreen.
SmartScreen is a bit overprotective and it can sometimes block software that is actually OK. In addition to stopping bad software from running on the PC, it can also stop good software too, simply because it does not recognise it.
Here is an example of running a program that SmartScreen does not recognise. It is MusicBee, an alternative to Windows Media Player for playing music on your PC:
When this program is run on a Windows 8.1 computer, you will see a message on the screen that looks like this:
Windows has prevented this program from running because it is unrecognised and is therefore suspected of being malware. Sometimes SmartScreen is right and it really is malware, and so it is a good idea to scan the file with anti virus software.
Clicking the OK button removes the message, but does not run the program. If you are absolutely sure that the program is OK and it has been scanned for viruses, click the More info link.
This displays some information about the program in the bottom left corner and in the bottom right corner are two buttons. You have a choice and you can either run the program anyway, despite the SmartScreen warning, or don't run it.
In this case the program is OK, and clicking Run anyway runs the program as normal, and the installer for MusicBee starts.
You do have to be very careful about ignoring SmartScreen warnings, so really you do so at your own risk. When you are 100% sure a program is OK though, go ahead and run it. Always make sure that you have anti virus software installed. Thousands of programs work perfectly, but just one bad one can cause a lot of damage, so be safe.