I have a Dell Latitude D600 that worked perfectly fine, until around a few months ago. It starts up normally and takes me to a DELL startup and then takes me to a black screen that says this: Windows could not start because the following file is missing or corrupt: /WINDOWS/SYSTEM32/CONFIG/SYSTEM . It says I can repair the file by starting a windows setup CD, but I don't really want to spend the money to buy one. Is there any way I can burn the files onto a disk and use it like a setup disk?

Have you tried starting windows using the safe mode, and if it does start up in the safe mode, did you try to restore your system to a previous date that it was working properly. Sometimes when you have your kind of problem, even though several months have past, the calender for restore is lock too at the time your system went down. this gives you the opportunity to restore to a date close to when your system failed.
Before you try restore, make sure you do not have a virus that has corrupted you system, run a virus scan first. If you haven't done so I suggest downloading Malwarebytes anti-malware that is free online, it works very well, and Microsoft uses it for there systems.
I hope this is helpful, good luck, I hope you don't have to purchase the setup CD.