So I may have done some really stupid things. Let's start from the top as my disk drive was getting full on Windows 10, I moved my entire game folder to a new drive, by copy and pasting. Including Steam. I thought that was it, but it wasn't. So after deleting the copy of Fallout 4, to my modded version and making sure Steam would search my new drive in the settings Fallout 4 ran for a time. The game crashed in building menus so I tried to re-download my mods thinking that was the issue. After no change I re-downloaded Fallout 4. So nothing has worked so far, I think I'll need to uninstall Nexus Mod Manager and just reinstall everything.

Any other suggestions?

I think it might be good to uninstall all the mods in NMM. I believe you have an option in NMM to search for games on your system and hopefully it will find the location of the current install. Before installing mods you do want to make sure the Vanilla game is able to launch and play.

You might have to redownload your mods.

Steam needs to know where it is installed, I believe.
NMM can have its paths reconfigured once Steam and its apps are up and running properly.
Uninstalling the mods during this is also a good move.

Steam now knows where Fallout 4 is installed, It just refuses to run. On launch the game crashes before it starts. So maybe Erzherzoghans is on the right path I'll probably need to delete and re-download my mods.

My suggestion would be to delete the contents of your data\textures and data\meshes directories in your new install path.

You should have no .esp at the Data level. Don't mess with the Fallout 4 .ba2 files.

Then have Steam validate your game directory. It will download anything it needs.

Make sure FO4 starts with no mods installed at all first.

Well, you can't just move Steam.
You would have to uninstall Steam, reboot, and then reinstall Steam in a new location (on a different harddisk or whatever).
Even the games themselves, you can't just cut and paste them!
They are all registered (in Windows registry) in a certain location, and under certain parameters...

I have a 500GB WD Caviar Black STEAM_DISK F:\
While my savegames are written to C:\
And I have a big Windows swapfile on D:\
Which I believe is why I never have problems with my AutoSaves...
(Imagine if only one harddisk C:\ had to do all that stuff all by itself!)

Don't make it harder than it has to be.

Open Steam.

Upper left corner click Steam, then Settings.

Select Downloads, then click Steam Library Folders.

Specify the location you want for Fallout 4. If you copied the files manually, Steam will verify them, reregister them, but not re-download them.

Note: You could put each game on a different drive if you wanted. And had a lot of drives.

Done.

So X-Com 2 runs just fine, I followed the directions here. https://support.steampowered.com/kb_article.php?ref=7418-YUBN-8129. Deleted everything but Steamapps and Steam.EXE. Logged back in and X-Com 2 boots up, but Fallout 4 does not. Is there a crash log out there for Fallout?

Right well issue one seems to be a driver issue. After updating my driver Fallout 4 loads. However issue 2 which is me crashing in the build menu. I don't know what mod is causing that.

GameMode=Fallout4

Fallout4.esm=1

ArmorKeywords.esm=1

Damage Threshold.esm=1

Robot Home Defence.esm=1

Snap'n Build.esm=1

CBBE.esp=1

Armorsmith Extended.esp=1

Combat_Helmet_Illumination 1.2.esp=1

Companion Infinite Ammo and Unbreakable Power Armour.esp=1

DarkerNightsDetection.esp=1

DarkerNights.esp=1

DV-Deadly Vertibirds.esp=1

DV-No Levelled Vertibirds.esp=1

DV-Armored Pilots.esp=1

Fr4nssonsLightTweaks.esp=1

Weaponry Overhaul.esp=1

FO4LaserBolts.esp=1

LegendaryModification.esp=1

Lore Friendly Posters.esp=1

Northland Diggers.esp=1

OCDecorator.esp=1

OCDispenser.esp=1

RaiderOverhaul.esp=1

Raider Overhaul - AE Patch.esp=1

Realistic Survival Damage.esp=1

ScrapDeadThings.esp=1

Simple Intersection.esp=1

BetterJunkFences.esp=1

SC_ExpandedBuildings.esp=1

SC_ExpandedConcrete.esp=1

SC_ExpandedDirtGrass.esp=1

SC_ExpandedHedges.esp=1

SpringCleaning.esp=1

This is MY Bed (Extended).esp=1

DeathclawDT15.esp=1

TrueStormsFO4.esp=1

TrueStormsFO4-ClimateSettings.esp=1

TrueStormsFO4-GlowingSeaExtraRads.esp=1

DarkerNights-TrueStorms.esp=1

UndyingPatriotStandalone.esp=1

Molerat_Disease_Immunity_PA_Hazmat.esp=1

Water Sources Expanded.esp=1

My_Minutemen.esp=1

Armored General by Hothtrooper44.esp=1

BOS_X01_Paintjobs.esp=1

DD_build_a_castle_01.esp=1

DX Commonwealth Shorts.esp=1

CSEMod.esp=1

DD_CBBE_SLooty_Castle_Innie_Vajayjay_4k_Fix.esp=1

DD_fire_lights.esp=1

DD_Columnsandstuff_1_0.esp=1

DD_AIO_I_Hate_You_All.esp=1

Eli_ArmourCollection.esp=1

Eli_RuggedOutfits.esp=1

EctoPaint.esp=1

GBJumpsuit.esp=1

Impervious Power Armour.esp=1

BetterShackBridges.esp=1

Institute Clean.esp=1

DD_M79_Launcher_woooot.esp=1

Rangergearnew.esp=1

Anchorage Power Armor.esp=1

OutcastT60.esp=1

OutcastT45.esp=1

BKFT_Outlaw.esp=1

PlasmaGatling.esp=1

SettleObjExpandPack.esp=1

Snap'n Build - Modules.esp=1

M14.esp=1

Skibs223Pistol.esp=1

Witcher - Geralt's Prologue Gear.esp=1

GaussRifleMk2.esp=1

GaussRifleMk2 - AWKCR.esp=1

Enclave-Standard-Navarro.esp=1

AutoDoors.esp=1

SettleObjExpandPack-AutoDoorsPatch.esp=1