Sonar 8 & Focusrite Saffire USB - no audio

Hi,
Complete newbie with Sonar 8 and I having problems getting any audio into Sonar.
I have the latest Saffire drivers installed.
Sonar appears to "see" the hardware
The Saffire 6 is getting a good line-in signal as the Sig LED illuminates in time with the source and I can hear via the headphone socket on the Saffire 6
As a test I configured a single stereo track and selected inputs to be Saffire 6 Stereo and output to Saffire 6, I hit the arm button, playback my source (using my phone playing a stereo track) and Sonar shows no activity on the meters and seems to be doing nothing - what am I doing wrong here?
 
I have screenshots, but seeing as I am new it will not let me post them.
 

Where is that located? I followed the audio set-up guide and didn't see that.
 
Ok, found it, I'll give it a try.

Yep, got it, to the right of the arm button, still nothing though.

Ok, it's a weird one.  It refused to work, even after rebooting the PC twice.
 
I decided to pull the USB cord out from the Saffire 6, and then plugged in back in again and it has now all come to life. So, power-cycling the Saffire 6 seems to have done the trick for whatever reason.
 
I'm just getting back into DAW/DTM after not doing anything for over a decade, so I'm not a complete newbie, I started out using several Atari1040STE, then PCs using ****base  for years (I loathed the dongle!), ACID, Fruity Loops etc. 
 
Thanks for your help, much appreciated.

It would help to know what your setup is. Computer brand, operating system, how much RAM, etc. Also, do you know how to disable your onboard sound card? If not, I will try to help.

Sorry yes, should have given you the environment info.
 
Onboard card is disabled, at OS level, still enabled in the BIOS for now.
 
Windows 7 64-bit
Intel Core 2 Q9300 2.5GHz
Mainboard Gigabyte P35C-DS3R
8GB of RAM
OS and apps on 250SSD
DATA on  2 x 1TB drives
 
Everything is working fine now.

I don't know how old your Saffire is but I would like to give you this tip. I don't know what's causing it but I always have to let the computer boot up with the Saffire hooked up. After the boot the Saffire is always distorted sounding. I simply unplug the USB and plug it back in after it has completely shutdown. Then the sound is crystal clear. I have asked for help on here but no one seems interested or has an explanation. I don't know if yours will have this behavior but mine has had it since running in Windows 7. Again, if someone has an explanation I would love to see it here.