wont record?

my digi recorder stopped recording sat 13 march2010. reset it lost all previous recording so not full up. going in to planned recordings and they are still there but nothing is happening (perhaps don't like what i record)this is getting really annoying as we have 3 of these machines in this household and each has been replaced at least once and none is over 18months for various reasons. when themachine is working it's brilliant but different matter when it's not. any suggestions other than a hammer.