Lou, welcome to iRV2.com. We are glad to have you join us here and we look forward to reading of your adventures and experiences. Did you have trouble before replacing battery? If not, could you have a wire for the slide room not attached or attached to the wrong post on the battery? Follow the positive cables off the batttery. You should come to a circuit breaker or two. Make sure the is power getting on the load side of the breakers. Retry slideout. I would recommend the next time you change the battery out that you consider a deep cycle battery over a cranking battery. Let us know what you find. I think you may have a breaker tripped. If it is a manual reset type, you will need to puch the little button back in on the end of it.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7