RF module

Hello;
First i want to describe about my project. In my project their are two RF-transmitter Receiver pair one to the Micro-controller(16F877A)
side & another pair is to the my computer (Desktop) side.
Case 1: When one Transmitter to the PC side ( RF Transmitter connected to my PC through MAX232). and one RF-Receiver to 16F877a.
Here i m sending some massage from PC connected RF- Transmitter. to --------->Micro-controller connected RF- Receiver
My controller read the data through RF Receiver and compare with text & doing what i want (like on fan ,displaying temp).

Case2: Now i m taking one RF-pair( RF transmitter & RF-Receiver )to the PC side and one pair (RF-transmitter & RF-Receiver ) to the 16F877A side.
And here i want that, when i send massage from my PC-connected RF-Transmitter to RF-Receiver connected to 16F877a .The 16f877a should send the Temp through RF transmitter to the PC -connected Receiver . and though This i can display Temp on My computer.

Now my problem is First case is working fine.
when i m using case 2.I m unable on-off any device ,or display temp .
but in case2 when i m cut the wire of RF Recever of my 16f877a it is workig (means case2 working as case1)
how i can resolve the problem . Please help me.

Is it needed different type of RF pair?

Only supply power to either transmitter while sending.
While it has power, a transmitter will jam the other, and swamp its own receiver.

yes sir. as i have written that when i removing the the Transmitter circuit (by mistake i have written receiver in case-2 in earlier post )in micro controller side it working it receiving the massage.