Win7 Locks Up on Boot -- Related to CD-DVD Optical Disk Drive

I am using an HP Pavillion DV9700 laptop
BIOS F.2C
AMD Turion 64x2 TL-60 2.00 GHz
2 GB on board
Windows 7 Home Premium, 32-bit OS, all updates installed

Somewhere, after a Win7 update many months ago, the problem started. I had no problems before. It started with the OS not recognizing the optical disk drive that came installed with the laptop. The computer's set-up BIOS recognizes the drive as being there. The optical drive does not show in Device Manager.

I tried changing out the disk drive, it did not help. Soon, Win7 would occasionally lock up at the boot screen, but work fine on a cold reboot following a lock-up. But then the lock-ups became permanent and cyclical. No amount of reboots would help.

I went to do a clean install using an external USB optical drive and accidentally discovered it cured the problem! The laptop will not lock up if the external USB optical drive is hooked up and turned on when starting the computer.

I tried a clean install of the operating system. I tried updating the drivers. Nothing helped.

Win7 always recognizes I had problems booting and sends the error messages to Microsoft.

Any help would be appreciated.

Thanks in advance.

I tried popping out the internal optical drive and keeping the USB optical drive off, and Win7 locked up on boot.

I turned it off and restarted with the internal optical drive still out but this time with the external turned on, and it booted just fine.

Thanks for your help.

I want to make sure I am clear with my description of my problem.

There appears to be no problem between my computer Set-up and optical drive. The computer boots with no problem and the optical drive is recognized in the Set-Up.

When I said it is "locking up on boot," I meant when Win7 boots. When it is loading, the "Starting Windows" screen locks. I never see the Log-in screen.