Ntldr Missing Vostro 1700 Need Help!!!

So yesterday i went to go put in a new hard drive into a vostro 1700, which has 2 hdd slots. in the first slot there is a 160gb hard drive, that has important data and the windows xp operating system. The second drive that i was putting in was from another computer and it also had an operating system on it. so i popped it in the unused slot, and then went to boot. I get the this message "NTLDR IS MISSING PRESS ANY KEY TO REBOOT". so i did and the message popped up over and over every time i pressed a key. i removed the second hard drive and replaced the cover and tried to boot with the same issue. so i googled it and found this guide.Simple "ntldr is missing" fix with boot floppy, CD-R, or USB flash

I was able to make a bootable usb and it allowed me to get into the hard drive and run windows off of it, like it normally does without safemode or anything. then i replaced the files like it said and rebooted. i got the same error message and i could not boot. so i booted from the usb and got into windows again. the files i replaced were the "boot.ini", NTLDR, and NTDETECT.COM.

Im not sure what to do now. please help!!!

 

If you got all your files off of the drive, I'd say you should just try reinstalling Windows...

 

Ok another small problem its my mom's work computer and she has a deadline tomorrow. so i cant just go and reinstall windows. that would take a few hours which she doesn't don't have.

edit: breaking news my mom has agreed to try this later tonight.

edit: somehow i was able to fix it, by restoring the boot.ini file to what it was when i started and it worked thanks for the help!