I recently had the experience of having my Windows NT session refuse to start claiming that one of the files that it needed to be able to start had gone missing. As a result of this I ended up making several different attempts to recover my system, some of the things I tried made things worse rather than better so I will share my experience here and make some suggestions of things that you should and shouldn't try in attempting to recover your system
The first thing to do when your system refuses to start is to try the options available during the startup process to see if they will allow you to get your system to start. The first of these to try is to press the space bar when the message comes up to do so if you want to use the previous working configuration. If this doesn't work then select to start in VGA mode when the start menu appears and see if this helps.
If neither of these things works (as in my case) then it is time to get out your original Windows NT installation disks.
What you need to do now is to start the install process just as you did when you originally installed Windows NT but instead of pressing enter to do a brand new install press 'R' to tell the system that you want to try to repair the current installation. Unfortunately, if you didn't create a repair disk or have made changes to your system since creating the repair disk the NT session may not be able to be located in order for it to be repaired.
It was at this point that I made the mistake of attempting to reinstall from scratch after deleting the content of the drive partition. Doing this is not a good idea. This resulted in my losing all of the data stored on that drive partition (fortunately only my emails were stored here) and I then made the discovery that the backup tape that I had made would not restore successfully. This is definitely not the best time to find out that your backup doesn't work.
The better solution at this point is to start the install process again and at the appropriate point in the process select to upgrade the existing Windows NT session. It doesn't matter that the version on the disk is actually the same or a later version than the one you are "upgrading" to instead of being an earlier version as the effect of selecting to do this is to load the version from the original media in place of the corrupted one on your disk while preserving all of your programs and data intact. After you have done this you should then be able to reboot your computer and get your Windows NT session working again. All that you need to do then is to reinstall any service packs and Internet Explorer upgrades that you had installed subsequent to your original installation.
This article written by Stephen Chapman, Felgall Pty Ltd.