Hello Charlotte.
A stack works as a unit, You can't logging into switch 1 or switch 2, because they work as one, that's why you stack 3750. Question: How are you stacking the switches? ... using stack cables I hope... not with ethernet cables.
Post:
How are you stacking the switches?
How are you logging into the switches?
Show switch if possible? (maybe thru console cable)
Regards.
Wilson B.