It is possible to disable one key on the macbook's keyboard??

I have an Apple MacBook Pro Intel core2Duo 2,2 Ghz late 2007 (not unibody)

The key (4) sometimes begin and continue so

444444444444444444444444444

until when I do something

Right now the space in which there is the key is free, I pull up everything,

but anyway sometimes the 444444444444 start again