- Move shutdown before boot menu key  
- Explain to press-and-hold boot menu key before powering on 
- Link to website of computer vendors in list of boot menu keys
- Mention faulty USB sticks
#2 Updated by sajolida about 4 years ago
Regarding "Explain to press-and-hold boot menu key before powering on " this might actually be problematic on some BIOS.
Having a "key stuck" on a Thinkpad X400 leads to a BIOS error so simulating this problably does the same.