help with a MELSEC FX2n PLC

Theoretically you have all the necessary parts, as long as the cable has the adapter for mini-DIN connector (older cables for FX2C and earlier did not have it).

I recommend that you first execute a clear-all and if the project also has a copy of the data of the D's memory area also transfer it after having transferred the parameters and the program.

I would slightly disagree.
Reinstating data (D registers) can have unforseen consequences.
If they are saved in the program (highly unlikely) they would have been saved at a certain point in the automation.
No telling where that would be.

As for your setup.... win 95 needs a batch file to use the com ports.
Medoc is tricky to the uninitiated as it is a dos program.

You have all you need but good luck.

About D registers: All the data was lost with battery failure. If there is a copy of those registers in the project, that should be the starting point because it is the only one available. I still recommend that they be transferred ( if the project.dwr file exist)

If they were saved later versions then obviously he should use the more recent set.

I remember that Medoc still worked pretty well in Windows 95, the problems came later with the following versions of Windows.

The latest versions of Medoc, I believe it was v2.3 or 2.4 were also optimized for Windows and I remember having used them on Windows XP without major problems.
Good luck !

You must be a thinking of file registers. A different thing.

I mean the battery backed D registers that can contain configuration values.

On the FX2n file registers occupy the same area that D battery backed registers: from D1000 to D7999

Melsec Medoc does not save D registers automatically. It is a separate procedure, which creates a .dwr file. If there is no such, there is no data backup. The logic, however, may be not relying on any non-volatile data in the registers.
Also, Medoc has no ability to save the latched M bits status. I there are such in the logic, they will have to be properly set manually.