I have an RCA RTD325W DVD home theater system that I am trying to control with an RCA RCRP05B universal remote. Ive tried all the different modes and all the associated codes and I cant get the remote to control the home theater system. I would just be happy for the remote to control the audio part of the system if I had to settle honestly. Any help would be apprectiated.

I don't know about this particular model but most RCA home theater systems will respond at least partially to Audio 1254 and to Video 1022, 1060, or 1132.

If you can get response from any button (try lots of buttons), then we will be able to get everything working.

Ok, first off thank you for the response. I was able to control the volume of the home theater system using the audio mode after inputting the 1254 code. The problem now is that I cannot use the universal remote to turn the home theater on or off, only to adjust the volume.

Please try the following EFCs with the unit turned on to see if they will toggle power, or turn it off:
18192
51472
18704
51216
18448
19216
51728
18960

Test in Audio mode, with 1254 as the setup code. Tap Setup (don't hold it) and then enter the 5 digit EFC. When the 5th digit is pressed, the remote will send the IR signal. Holding the 5th digit will cause the signal to repeat. To verify that the procedure is correct, first try it with 51988. That should turn the volume down.

If one of these functions as Power toggle, you can assign it to a button (unfortunately not the Power button-- use Live instead) using the 994 command.