There are two way to check.first is you can directly check whether key contain A or not in binding like this:-. but i think this is not the better way so instead of this you can use ko.computed to check.
Check for operating system information in Windows 7. 1  Click the Start button , enter Computer in the search box, right-click Computer, and then click Properties. 2  Look under Windows edition for the version and edition of Windows that your PC is running.
Log in to a user account in Windows. Click Start and then Control Panel.. Click Programs and then choose Programs and Features option. Scroll down the list that contains all software that is installed on your computer.The column Installed On specifies a date on which a particular program was installed.og in to a user account in Windows. Click Start and open Control Panel.. Click Add or Remove Programs.. Scroll down the program list to see software installed on your computer.