What does Y2K Joke actually do during its diagnostic sequence?

Y2K Joke puts on an elaborate fake show:

• Simulates scanning and "fixing" your BIOS for Y2K compliance
• Pretends to test and repair your mouse
• Runs a fake monitor diagnostic
• Changes all letter Ys to Ks in the display text
• Plays audio that claims to detect a critical error
• Instructs the user to physically tilt their desktop computer on its side

None of these actions actually affect your computer in any way -- it is all for laughs.