Please reinstall <windows root>\system32\ntoskrnl.exe

I have a Dell Latitude D600. Last year I had the hard drive and disc drive replaced. Now I get the message to re-install <windows root>\sysem32\ntoskrnl.exe. I can't get my computor to run the windows disc to re-install the software. I have tried starting my computor in "safe mode", that doesn't get me anywhere, I have tried starting my computor to the last know configeration where everything worked, that doesn't work. I have tried pressing the windows key and R to get the computor to run the disc, that doesn't work. How am I supposed to re-install the file? I am really a dummy when it comes to this stuff....... so the easiest explanation would be appreciated. Like "step by step" directions. LOL Thanks so much to anyone who will HELP!!!!

"Last year I had the hard drive and disc drive replaced"

Who did this for you? Are you trying to re-install XP from a Dell CD?

I had a gentleman who worked with my Husband install the hrd drive and disc drive. He is the ITT man for their company. I was trying to re-install Widows XP from a disc I had purchased with Service Pack 2. That was the only disc I could find that had the software for Windows XP on it.

You need to place the XP CD in the drive and restart the laptop. As the laptop starts booting, you should see "press any key to boot from the CD"... Press a key and the XP install will start. You are re-installing XP not just a single file

That doesn't work. I put the disc in the drive, turned off the computor and re started it. It just gave me a black screen that says:
windows could not start because the following file is missing or corrupt: <windows root>\system32\ntoskrnl.exe.

It won't let me do anything else.

You have a bad hard drive...

Thanks, I will contact the guy who replaced the hard drive last year. It was supposed to be a new drive. Shouldn't have given up the ghost this soon. There is hardly anything on my laptop as far as software and files goes.