I have to debug a program made from NE-files (NE=New Executable) but not from PE-files. (Lets call it X-program.) OllyDbg does not support at all 16-bit files, so I can not use OllyDbg to debug the program. TRW can debug NE-files but it does not support Win2000 and WinXP. I have WinXP +SP2 on my PC. That program is fully functional Windows program with graphical user interface although its files are New Executable, the old DOS format NE-exe. That program runs due to wowexec.exe and ntvdm.exe processes.
I was told to use SoftIce for Win9x that can process 16-bit aaplications. I have to convert the *.MAP file to *.NMS file using the tools MSYM.EXE, NMSYM.EXE, WLDR.EXE, coming with the SoftIce pack together. The *.NMS file is the SoftIce symbol file that SoftIce needs. But there are two problems. First - can SoftIce for Win9x run on WinXP+SP2 system? Second - I do not have a MAP-file. As far as I know the MAP-file is generated from the linker when the program is linked from the object modules. I just want to reverse the X-program to find how the serial number is verified and to make a keygen.
PE-Explorer also does not want to process not PE-files (well, its called PE-Explorer not NE-Explorer ). I just want to examine the resources, probably to find the registration form dialog box, but I don't know how to proceed.
Please help me!

You may want to look at turbo debugger also.

I already tried to use TDW. But it wants symbol table. The same problem as the mentioned above - I do not have symbol table for the X-program, because the X-program is not my program. Furthermore when I start debugging (F8 or F9) TDW gives me "Exception 13, Error code 0" and does not want to start debugging. So what shall I do?

Several alternatives:

1. Make a small partition in your HD and install win98, Driverstudio 2.7, your program, tools etc.

2. Learn to use VMWARE, create a virtual machine, install win98 etc, etc Installing and making SoftIce work inside VMWARE is tricky, but can be done.

3. SoftIce 3.2 CAN trace NE- executables in winXP if you load them via a cmd based window using loaders provided by Sice. search the board, I did mention this technique in other posts. This alternative is shaky at best

Here, look at post #14
http://woodmann.com/forum/showthread.php?t=7712&highlight=16+bit

Thank you very much Naides for the answer. And the next question is can SoftIce 3.2 trace NE- executables in winXP without a symbol table file? Without *.NMS file?

SoftICE can trace virtually anything (be careful of breaking in a driver though).