When I turn my mac on it make a sound like "tou" 5 times every 20 seconds and the screen does not show anything.
iMac, OS X Mavericks (10.9.3)
This might be "Bad checksum for the ROM boot block".
You can find more here
http://support.apple.com/kb/HT1547
1 beep = no RAM installed
2 beeps = incompatible RAM types
3 beeps = no good banks
4 beeps = no good boot images in the boot ROM (and/or bad sys config block)
5 beeps = processor is not usable
when I turn on my mac it make a sound like "tou" for 4 times every 20 seconds and the screen does not show anything
