Arduino Mega 2560 installation error

Hi,

I am trying to install the driver for my Arduino Mega 2560 but something keeps going wrong.

I am using a windows 8 tablet and have being going through the standard process but every time I click install I get this message,
"
windows found driver software for your device but failed to install it.

Arduino Mega 2560

A problem was encountered while trying to add the driver to the store
"

I looked at the tips on the forum posting rules but it was beyond me and I was hoping some one would have the patience to walk me through what ever is going on.

I also get the error "serial port COM1 not found" when I got to the Adruino program, tools, serial monitor

Thanks

Did you ever solve this problem? I've got the same situation.