It's my understanding that squash seeds remain viable for several years, but soil & storage conditions can effect any seed's viability. (Duh, I might add that I've been reading your posts for several years, & believe that you are storing them properly.)
Did you plant your squash seeds recently, or was it a few months ago? Some seeds seem to know when it's "planting season", & the only way to trick them into sprouting at other times is to start them indoors.
The only way I know of to test them is to put them between a couple layers of wet paper toweling or a paper napkin, enclose that in a baggie & put it in a warm place... if they're still good, squash seeds should sprout within a week or so (give or take a few days). Go from there, & if you're planting now it might be best to continue them indoors until they develop true leaves.
Don't forget to harden them off before replanting outdoors.