I have a HP Pavilion dv6-1107X Entertainment Series notebook. When I turn it on I get an inconsisent series of very loud short beeps nearly always in 3 groups. First group can be 4 to 6 beeps. Second group can be 1 or 2. Third group just goes on and on until the Windows Boot Manager pops up. Once I select the Vista operating system everything appears to start working as normal.
Here is what I have done:
1. Replaced motherboard and CPU
2. Checked and tested hard drive by diagnostic and in another machine - okay
3. Have used a known good hard drive in this machine - same symptoms, no change.
4. Checked and tested RAM stick in both slots, by diagnostic test and on another machine - okay
5. Did a Factory Default recovery - Operating System (OS) behaved erratically.
6. Did a Clean Install using another machine - OS works but same symptoms as above with beeps and Windows Boot Manager.
7. Installed all required drivers as required in Device Manager (after a LOT of problems trying to find the HP driver download support - I had to search for HP Compaq Pavilion dv6-1107AX to find a site that linked to the driver downloads).
8. Have run AVG anti virus, and 3 x anti spyware (Malwarebytes, Spybot and SuperAntiSpyware). Nil bugs founds.
9. Reset BIOS to defaults.
Am also having problems from time to time access BIOS. It takes several attempts but can be gained by pressing F10 immediately after the first screen with ESC option on it. Also have problems access Safe Mode using F8 but perserverance is required and it will work eventually.
Has anyone any other ideas please? Am afraid I've run out of them.
Hoping, hoping, hoping ..... 
Russ