windows nt/98 dual boot changing partition drive letters

[hiqserv]

 I have an old Dell precision 210 workstation that came with windows 98 se and Windows nt sp4.  It had one hard drive partitioned into fat16 for 98 and ntfs for nt.  I have an expensive 3d cad software package that I used for years.  My hard drive filled up and so after a long battle, I have a second hard drive installed, same type as the original, but larger capacity.
I had all kinds of issues getting everything to work, but now i can reach all the drives, usb and cds.  Now the problem.

Doing all of this I now have a: floppy drive, b: nothing, C: windows 98, D: nothing, E: windows nt, F: second hard drive ntfs G: fat16 H: cdrom. 

I cant afford to update the software, the company wont do anything for me unless i pay for maintenance for the last ten years.  I need the software, But the software files for it to load look for D:..... to run it.  The files are on the E Drive, and I cant reinstall them. 

I want to use the D: drive, which does not exist,( error message D:\ is not accessible, volume does not contain a recognized file system) by swapping the E: for the D: letters. From what I read this is not possible.  I don't know how to go into the software and change the pointer from D: to E:

Any suggestions?  I am fairly good with computers, not a programer, but I got this far on my own.
Thanks in advance

[ngc2392]

Wow, that's ancient time, my friend Really can't help you there since I all but forgot those days...
But, just out of curiosity...is that 3d cad software so special that you can't use something similar? Like free https://www.nanocad.com/ or https://www.freecadweb.org/?

[hiqserv]

Hi:

Yes I started with it in 1985 bought my lisence in 1997 .  It was SDRC now it is owned by Siemens.  Does full blown, 3d solids, surfaces, and mechanism calculations.  was $16,000 new back then.  and have used it since,  Works great for my type of design, generates 2d drawings automatically, can update using variables. and i have 35 years of projects on it that I still have to access. 

I grew up with dos then unix then nt to what it is now.  Thanks for the input.

[BC_Programmer]

You should be able to change Drive letters in Windows NT with Disk Administrator.

[hiqserv]

thanks for the tip.  I had to dig to find the file, read thru an explanation online, opened the file, and it doesnt really tell me if I can swap a drive letter.  I can assign one after formating. but doesnt seem to indicate changing a drive letter after it is assigned.

the D: partition is open nothing in it doesnt show a format. just size.  thats the one i want to swap with the E:

Again Thanks for the reply;

[ngc2392]

OK, but if you put that disk in other pc, can you access the data or not? Maybe the disk itself is faulty (got bad sectors...)? One option is also virtual os where you can install that sdrc-if you have install files, of course.

[BC_Programmer]

thanks for the tip.  I had to dig to find the file, read thru an explanation online, opened the file, and it doesnt really tell me if I can swap a drive letter.  I can assign one after formating. but doesnt seem to indicate changing a drive letter after it is assigned.

When a disk partition is selected, you can use the Tools menu to assign a drive letter, change the assigned drive letter, or unassign a drive letter. You can also access this by right-clicking the disk volume. You can use this to swap drive letter assignments.

Let's say You have Disk 1 = D: and Disk 2 = E:

Unassign the drive letter from Disk 2, Assign Disk 1 to E: assign Disk 2 to D:.