You can use Microsoft Expression Encoder 4 to capture your screen. You are able to capture 10 minutes with the free version of Microsoft Expression.
Download and install Microsoft Expression Encoder 4
After the install select ‘Microsoft Expression Encode 4 Screen Capture’
Select ‘Settings’ to configure the Screen Capture
Click ‘Audio’ and select the microphone that you want to use
Close settings and click ‘Record’ to select the capture size.
Click ‘Record’ again to start recording the video
Click ‘Stop Capture’ to stop the capture
Select the recent capture and click ‘Send to Encoder’
View your capture and click ‘Encode’ if its useable.
When the video is encoded and you use the default configuration of Expression Encoder 4 you can find the video on Documents/Expression/Expression Encoder/Output/<Name of video>