problems with cubase artist 8

hi, i am enquiring about some problems i’m having with my cubase artist 8.

here’s the scenario: my most recent project has 2 channels only; a guitar vocal through the first and a groove agent signal through the other. there have never been any problems with my new purchase until today. i turned the system on to add work on my latest project and found the sound had been disabled. i checked the settings in case i had maybe saved them another way without noticing but everything was as should have been. i played past recordings that had been downloaded onto another format to see if the computer itself wasn’t working but this was working ok. further to this i discovered the search back and forward on the transport panel is disabled. i loaded a fresh new project to see if loading other channels of groove agent would start the system working again but found when i opened the preset drum pattern pads they wouldn’t play. also there is the other projects i have saved on cubase artist 8. they also won’t play. the sound is disabled and again the scroll function on the transport panel is jammed.

the basic problems (i discovered today at least) are the sound is disabled, the scroll function is jammed and the pre loaded drum parts in groove agent won’t play. how can i resolve these problems?