Without the remote, press the Menu button on the side of the TV. Select Picture Mode and then scroll to Screen Format (second item) and select that. Use the left right arrow to try different formats. Press Menu repeatedly to exit the menu system.
Use the ch + and ch - buttons to go up and down. Use the Vol + button to mimic the left arrow and the Vol - button for the right arrow. Press Menu again to select an item or for OK.
The manual is available from the manufacturer. The direct link for the English version is:
http://support.ttetech.com/RCATV/Assets/PDFs/L32HD31_E001A_IB_e-08.pdf . If the direct link doesn't work, start here:
http://support.ttetech.com/en-us/productdownloads.html and use the drop down menu to select 32" TV and then L32HD31.
If you would like a replacement remote, try here:
http://www.rca.newremotecontrol.com/catalog_item.php?catnum=275576 . Otherwise, most universal remotes will work the basic functions if they were programmed 6 months or more after the TV was released. However, you probably will want one that can match the Format (Left arrow) button as well as the input button. This probably will not be available in the most basic universal remotes. (It is guaranteed to be in those remotes that can be programmed through a USB connection to a computer.)
I hope this helps.
Cindy Wells