hardest pc problem ever! bios/booting/os's/hardware

Alright, this is officially the first forum that i've ever used to solve a problem, usually i'm cool enough to figure things out. Now, this problem is fixable, i'm sure of it, however i've tried many things that i thought would've worked, that havent, and i'm gettin desperate.

Let me explain you the problem in detail

My friend had a lot of spyware on his computer, so me and another friend decided to use some programs to help fix it up. During our extensive fixing, We ran a registry cleaning program and installed a new version of internet explorer, somehow, one of the registry files (shlwapi.dll) was replaced with an older version and windows had to be reinstalled,

this didn't seem too hard to fix, simply reinstall windows right?

WRONG! When we inserted the windows disk, we found that it didn't boot up when we started the computer! Neither did floppy disks! ahh... but hey no Biggie...

-I wasn't entirely sure why it didn't boot, so i took out the hard drive, I found that the computer booted when the hard drive wasn't connected to the motherboard. I realized that the boot settings must have been set to a different order, ( to: hard drive, cd drive, floppy ) ...

-so change the settings right? well, there's a password on the bios and i've tried many things but i can't manage to crack it , my friend recently bought the pc from someone who sells old pc's and found that he was provided with the user password but not the administrator password that let's you access bios, and ms-dos, and boot selection screens.

- I installed a newer version of the bios from the toshiba website, however, the passwords remained in the bios chip. Also, it's a laptop, and i tried opening it up, but there was a nonfactory screw in it? wierd....

- I tried putting the hard drive in another laptop and re-installing windows to the hard drive using the other laptop, only to realize that that really doesn't work when you put the hard drive back into the other computer.

- Then i formatted the hard drive and tried to install again. Only resulting in failure...

So now i have this formatted hard drive, I have the ability to add files onto it using the other computer, but i really need to be able to install windows onto it from it's original computer that doesn't boot,

i tried installing Ms-dos 7.1 onto the hard-drive, making it the primary os, but somehow it didn't work idk why (maybe i need a different installation software,

i also tried linux, but the cd was malfunctioning...

so if you have any advice i'd take it happily, it's a toshiba sattellite pro 4260dvd with a phoenix bios,


thanks a lot!