Ok, knowing the source helps.. other than the fact that you are using a disk, this .. as far as I know of, should help & also work for any other mega mods you want to see of doing, beyond FotRSU-EN v1.1 (& any subsequent updates to it...).
Since you know about CCleaner, that's a leg up on the whole process... ad in the things that XS mentioned of ensuring that any & all files in the clean SH4 are ear marked as being capable of being written to, is something that I missed when I pulled this guide together (& shall update it, after getting a bit of sleep after posting this..

)
Other than that, this should get you fully up & skippering a boat in no time. I Have We dive at dawn, a pre Pearl FotRSU-EN v1.1 (patched, by the way with the patch notated at the top of post #1 in the forum thread for it), Operation Monsun Enhanced: Dark Waters, a sub squad 50 mix am in the works of setting up, as well.. and last but NOT least.. an IJN reserved copy of SH4, ready to rock & roll, just as soon as that hits the release status for it.. Climb Mount Niitaka...

that was a mouthful...
Ok, so any way.. on to the guide, just be warned.. it is long, but I believe useful.
I posted about another having issues with something close to this, in the FotRS subgroup here...
I have win 10 Pro edition 1909 (updated to latest in release as it stands at this time...)
I do run a 2 HD set up in my computer.. so I have the main ( C:/ ) & the 2ndary ( E:/ ... somehow the backup side of C:/, got named D:/ ... don't ask me how or why, it just happened when I added in another HD & then set the new 1 to be the main HD... C:/ is a 2TB E:/ is a .5 TB drive...)
I have Origin, Steam & Uplay launchers, set up & installed on the 2ndary... in C:/ I set up a folder called /Games, and this is where I install games at.
I have paid access to SH3, 4 & 5, through both Steam & Ubi...
Until about a couple of weeks ago, I had 1 copy of SH4 from each of them & modded out as to how I wanted to, at the time.. until I decided I wanted to add another mod into the mix & was unable to since I couldn't get a copy of SH4 from either place... since I had already d/l'ed, installed them.
So, I ended up having to dump & start from jump street.
I 1st tried after going through the painful process of uninstalling, clearing out every trace of having installed SH4, I then ran CCleaner to finalize the process & restarted my computer.
Then began the process of setting up a fresh clean.. of which I started with Ubi... which despite everything I found of how to make multi copies of SH4 to be able to mod it, whilst keeping a clean safe copy... that attempt was a bust.. a no go... a bomb.... no matter what I did, I could not get them to work.. so.. I gave up with Ubi..
I then turned to Steam & to date, have NO issues running SH4 modded (more than 1 copy of it, to be exact..) & have them modded to the following flavors:
FotRS-U-EN
Oper. Monsun: Enhanced
Oper. Monsun: Dark Waters
All while still having a fresh unmodded copy of SH4, available to copy from, should I desire to & I did so in the following manner..
With Steam, I told it to install the library in C:\Games\Silent-Hunter\SH4-Steam
In SH4-Steam, which is where I told Steam to put SH4 (v1.5, mind you, by the way...).
So the structure reads as follows there:
C:\Games\Silent-Hunter\SH4-Steam\steamapps\common\Silent Hunters wolves of the pacific (the last bit I just left as steam installed it.. it works & yanno the old sayin'... if it ain't broke.. don't mess with it... *shrugs*) after getting SH4 installed, I ran it to ensure if any further set up was needed & then shut SH4 down. After that I added in jsgme, multiSH4 and closed out & back to showing \Silent Hunters wolves of the pacific folder. Now, ready to play doctor accordingly...
Ok, from there, I created in \common
a folder named to what flavor mod I want to run with, for this ex. I'll run with the mod Operation Monsun: Enhanced (created by Fifi.. thanks for your work Fifi)
After creating that folder I then reopen the fresh, UNMODDED SH4 folder & using Cntrl+A highlight everything in there, right click & copy it all.
page back to \common & click on the new folder (OperationMonsun:Enhanced) & paste the game guts into it...
Having successfully made a fresh copy of SH4 then I begin the modding process...
I run jsgme, set up the mods folder, then close it out for the moment..
Next, I add in what all files & such is needed for the mod,send a copy of jsgme to desktop, renaming it on desktop to JSGME-OM:E, then run it & activate the mods installing in the prescribed order... once all mod parts are activated, I shut jsgme down & move on to the next step.
MultiSH4: I run this & set the save folder to the 3 letter nick, (in this case OME, for obvious reasons...) then close that out...
I make adjustments to 2 files, knowing full well what I want to do and how to accomplish this... I have a .txt note made for these changes which are minor & are as follows:
data\cfg\gameplay & data\cfg\main
gameplay, I adjust the realism to 4 key setting bells 'batteries, compressed air, O2 & fuel' & set these to +25, all the rest to =0 (yes I do activate everything to 100 for realism & go by the dead is dead principle... so no judgments, thanks... I do like having the ability to look about.. if i so desire to.. and yes, I know sailors then didn't have that luxury... is still nice though as it makes for some grand screenshots...)
Main, I adjust the time compression settings to what I want them down to, which is basically max compression of 1024... max.. I don't allow it any higher than that, as the limit. Doesn't mean I run TC to that point though...
After that, I then turn my attention to the SH4.exe, this I send a shortcut to desktop, which I then rename to SH4-Oper.Monsun:Enhanced
After I get all that done, I go to Large Address Aware, (which I have installed in C:\L-A-A, activate it & tell it to allow the game to use 4 GB RAM to run.. then after finalizing that process.. I turn my attention to the last detail...
run the game & enjoy...
Have NOT ran into any issue playing any of the mod flavors i have, only complaint I have is having to log into Steam, but that aside... they work.
p.s.
I do stop & run a check of the SH4 copy that I am going to play, as it were... Dr. Frankenstein on... but seeing as how my post was already starting to approach novella length.. I left it out of there, figuring that other would be smart enough to figure that out on their own...
At least I... never mind, any way...
I do keep jsgme & multiSH4 in a zip & already unzipped form, as back up in the 2ndary drive... for just such emergencies... if any thing happens to the unzipped copy, I can always replace it with running an unzip from where I keep that back up at there and replace the problem copy.. after deleting the problem one, that is... trust me... there is a methodology to my madness... and should all else fails, can always go out with a
As for L-A-A, that's just where I set it up to call home... to each their own, as long as they know it works, yanno...
Hope this helps...
Cheers,
Mad Mardigan