One thing you may notice is that the screen saver turns on (screen goes blank) very quickly after you have stopped typing. The reason is that Bochs simulates everything as fast as it can. If the CPU is very busy (running instructions nonstop), simulated time goes by slowly. If the CPU is idle (just waiting for you to type, for example), simulated time speeds up dramatically. In any case, if the screen saver blanks out the screen, just press a key (try shift or control) to restore the screen.
There are two strategies to fix this problem. One is to increase the ips parameter of the cpu option in your configuration file. This will cause the simulation time to pass more slowly. The other strategy is to enable the experimental realtime PIT, which tries to keep Bochs in sync with real time. See the bochsrc option clock.