Beeps when turning on your computer

The PC won't turn on properly, instead you hear patterns of beeps. They are actually built-in diagnostic alerts. They can tell you what's wrong. I got this from http://www.pcstats.com/articleview.cfm?articleID=1223 while googling what those beeps mean.

• No beep - no power, loose peripherals, bad motherboard or cpu
  
• One beep - ok
  
• One long, one short - motherboard problem
• 1 long, 2 short - video problem
• 1 long, 3 short - video problem
• 3 long - keyboard error
• Repeated long - memory error
• Continuous high, low - CPU overheating
  

I was trying to fix some old PC's in the lab since the students were complaining only 2 were working. Heard repeated long beeps in three computers - memory problem. Opened the hatch and placed the RAMS in a different slot and made sure they were snug and completely in.

Et voila! They worked!!!