Still waiting for root device after install? (the steady decline of my mac osx installs)

[norcalrivercat]

Ok so I have Zephyroth 10.5.2 rev. 1 and the dvd boots up fine. Originally I used to be able to install and boot right up. After a few re-installs (broke my system a few times) I get "still waiting for root device after the install". I chose all the same options. I must have tried to install it 10 different ways from just essential system software to clicking everything. The weird thing is, if I put my hard drive in an external usb case I can boot up and use the system just fine. But now after the first reboot when i boot externally (this didn't happen before by the way) I get an error like this: USBF: 34.293 AppleUSBEHCI[0x3910800] : : Found a transaction past the completion deadline on bus 0x53, timing out! (addr: 2,EP:1).

I have no idea what that means.

I have a HP Pavilion dv5000
AMD Turion 64.
ATI radeon express 200
IDE hard drive.
2 gig ram.

I don't know the motherboard, let me know if any more info would help in solving this problem and I'll try and look it up.

Any ideas to why this is happening, I don't understand why at one point it would boot internally and now it wont. And now it crashes externally as well. Any ideas, input or help is appreciated. I would really like to figure this out!

thanks!