I have been given an old DV6-2007EL HP Laptop (AMD Turion 2- M500 cpu & ATI HD4650 VGA)
The laptop shows a random problem: sometimes it correctly starts and load the OS, some others it just doesn't turn on, but:
Option a) All the leds are OFF; the fan works; if there is a CD the CD-Drive spins; black screen;
Option b) Bloc maiusc and Bloc scorr leds blink twice, then pause, then blink twice again, and so on. Again, the fan works, black screen...