HP dv6000 boot/hard drive/OS issues ?

Hi all,
As the title says, I'm having some trouble.
I'll start with the end result first - blank screen with a blinking cursor.
Specs -HP Pavilion dv6000 model dv6700- windows vista, 1024 MB memory, Phoenix BIOS F.52.
After spending 2 full days trying to figure this one out I give up.
I started with a full hard re set - pulled battery, memory,hard drive, power cord - re installed 1 memory board,power cord and powered up. Got a " no operating system " message. Fit the second memory board, battery and hard drive. Powered up and got the blank screen with blinking cursor.
Next try was a BIOS reset - pulled the memory and CMOS battery for an hour. Obvious BIOS reset as I had to reset the system time and date in the BIOS main menu screen. After exiting the BIOS utility I got the blank screen with a blinking cursor.
3rd attempt was a hard drive check. I pulled the hard drive and installed it into an external enclosure and plugged it into my desk top PC via USB. I had complete access to all data on the drive.
I re configured the BIOS on my PC to boot from the external enclosure and got absolutely nothing - not sure if this could be due to my PC being a Dell PC running Dell BIOS.
Any help with this would be greatly appreciated.
Jay