On January 27, 1967, a tragic fire killed the crew of Apollo 1 and destroyed the Command Module. I've read detailed reports about the engineering team that disassembled the Command Module. I haven't been able to find information about what happened to the rocket that was attached to the Command Module during the fire. Was it reused in a future mission? If so, which mission?
This is one case where Wikipedia says it all:
Apollo 1's (AS-204) Saturn IB rocket was taken down from Launch Complex 34, later reassembled at Launch complex 37B and used to launch Apollo 5, an unmanned Earth orbital test flight of the first lunar module, LM-1, in January 1968 .
The Wikipedia article cites the following primary reference:
"Apollo Program" (http://www.nasm.si.edu/research/arch/findaids/bellcomm/bci_sec_21.html). National Air and Space Museum. Bellcomm, Inc Technical Library Collection. Washington, D.C.: Smithsonian Institution. 2001. Subseries III.D.3. Accession No. XXXX-0093. Retrieved January 26, 2013.