[pcdavid]

The (probably very small) pieces of software on-board the Pioneer 10? It was launched in 1973 and has certainly never been touched since.

[Someone]

Pioneer 10 didn't/doesn't really have a computer. http://en.wikipedia.org/wiki/Pioneer_10#Power_and_communicat...:

"The spacecraft included two command decoders and a command distribution unit, a very limited form of processor, to direct operations on the spacecraft"

If we call what it has a computer, it was reprogrammed remotely:

"Much of the computation for the mission was performed on Earth and transmitted to the probe, where it was able to retain in memory up to five commands of the 222 possible entries by ground controllers"

That happened as late as March 2001 (and possibly even later, as communication was finally lost in January 2003): http://www.strobedata.com/home/pioneer10.html

[VLM]

Hasn't been heard from in 11 years, either. Maybe it crashed for all we know.

Voyager probes are still up and running but the power system has only perhaps one decade of useful life remaining as it declines.