A testing device for testing a printed circuit board includes a testing signal converting module for receiving testing signals from the printed circuit board and outputting the testing signals and a plurality of I/O control signals to a plurality of testing circuits. The testing signals include a BIOS signal, an audio signal and a floppy signal. A BIOS testing and upgrading circuit test the BIOS signal from the printed circuit board according to a first control signal and updating the BIOS according to a sixth control signal. An audio testing circuit for testing audio quality includes a line out/line in circuit for an output/input test, a hp-mic circuit for a headphone and microphone test and a speaker-cd-in circuit for a speaker/cd test. A floppy switching circuit tests a read/write function and a write-protect function of a floppy signal according to a fifth I/O control signal.