When you do not see the CDXStreamer option in the main Excel menu the addin has become deregistered. You need to see a reference to CDXStreamer in the COM Add in list for the formulas to calculate. This addin and the UDF add-in for CDXStreamer are required on your system. To check this use File-Options-Addins in Excel:
To correct this you need to add the CDXStreamer reference back manually but it involves browsing to a file named adxloader.CDXStreamer.dll (or adxloader64.CDXStreamer.dll for 64 Bit Excel). The path is the same as the CDXStreamerUDF addin on your system.
If you look at File-Options-Addins in Excel and click on CDXStreamerUDF you will see the addin "Location" in the text below. On Windows 7 this typically starts with C:\Users\[Your User Name]\AppData\Local\CDXStreamer. If you can, take a screen shot and print this out. If you don't see this path make sure your system is set up to view hidden files and folder. In the control panel of Windows 7 click on "Folder Options" and then "View" and select the option to view hidden files and folders.
Then click on File-Options-Addins again and select the Manage function (near the bottom of the dialog) and choose COM Add-ins. Choose the "Add" option and select the path to the adxloader.CDXStreamer.dll file and press OK.
This will restore the CDXStreamer function in Active application addins.
The other alternative is to set CDXStreamer up on another computer using your same username and password. There are no restrictions on setting up the app on multiple computers.