problem with sharp LC32SB23U

[bigwayne3000]

ok so my dad got a sharp LC32SB23U for xmas and we are trying to set this thing up. initially we had it hooked up just thru the cable box via coax cables, now we have these GE HDMI cords that we are using to connect the DVR/cable box to the TV. if the TV is on than we cant use the cable box controlls to switch channels/vol etc. if the TV is off than the controlls and cable box work fine. everything is hooked up correctly so i am not sure as to why this is happening. also im havign a problem with the local HD channels. the local ABC channel when we are on the channel the picture is in the center of the screen and is surrounded on all 4 sides by big black bars id say about 4" widths on all 4 sides. if i change the picture to stretch or to zoom etc via the tv controls than i have a problem with the cable box again. for example if i stretch it, itll be in widescreen mode but the Guide that i get on the bottom of my channels via the cable box become stretched and dont fit to screen. how do i remedy this problem? how can i set up this tv to just be widescreen or full screen on HD channels and have the cable box fit to screen without it being too big? sorry for this long post just lookign for any help. this has been very frustrating.