After you have ascertained that all necessary files are there in C:\ such as ntdetect.com, ntldr, boot.ini, (optional for W2K: cmldr) as well as autoexec.bat, config.sys, io.sys, msdos.sys (the last 4 all with filesize = 0), it's tyme to do a quick repair, using the Recovery Console.
If you have not yet installed it, insert the W2K CD:
1. Click Start, click Run, and then type CD-ROM drive letter:\i386\winnt32.exe /cmdcons in the Open box, where CD-ROM drive letter is the drive letter assigned to your CD-ROM drive.
2. Click OK, follow the instructions on the screen to finish Setup, and then restart your computer, booting from the W2K CD.
At the "Welcome to Setup" screen, press F10, or press R to repair, and then C to start the Recovery Console.
Run both fixboot and fixmbr.
FIXBOOT
fixboot drive name:
Writes new Windows 2000 boot sector code on the boot partition. This fixes problems where the Windows 2000 boot sector is corrupted. The Emergency Repair process also fixes the boot sector.
where drive name: is the drive letter where the boot sector will be written. This overrides the default of writing to the system boot partition.
FIXMBR
fixmbr device name
Repairs the master boot record (MBR) of the system partition. This is used in scenarios where a virus has damaged the MBR and Windows 2000 cannot start.
WARNING: This command has the potential to damage your partition tables if a virus is present or a hardware problem exists. This command may lead to inaccessible partitions. Microsoft suggests running antivirus software before using this command.
where device name is an optional device name that specifies the device that needs a new MBR. The name can be obtained from the output of the map command. If this is left blank, the boot device's MBR is fixed. For example:
fixmbr \device\harddisk2
If Fixmbr detects an invalid or non-standard partition table signature, it prompts you for permission before rewriting the MBR.
HTH