Digital BW, The Print

Hi All:

Two questions relating to my 1280:

1)  If a nozzle refuses to fire at all, and is not helped by liberal 
dosing with Windex, can I assume the printer is toast?  If not 
completely toast, is there a cost-effective repair?

2)  Could the above condition have been caused by my failure to 
remove the strip covering the air channels on the last cart installed 
until after I had run a bunch of cleaning cycles and nozzle checks?  
Are there any more likely causes?

Thanks in advance.

Chuck