Ok, strange problem, never had it before, crashing every time I try and save my game in megaton, only mod I have that MIGHT effect megaton is fook2, far as I know, no other mods effect it. In fact I recently started a new game after reinstall and alot less mods than I used to have to prevent crashes. Fook2 is the only overhaul of any kind I have.

it sounds like a load order issue to me, 'cause I know fook2 does a lot to megaton, do you have Fallout Mod Manager (fomm)? if so, given that fook2 is your only mod, besides the main esm and dlc's, your load order should go something like this (don't quote me on this):

fallout3.esm
Anchorage.esm
thepitt.esm
brokenSteel.esm
pointlookout.esm
zeta.esm
fook2.esm
(the fook2 [censored] thing).esm
(the fook2 DIK thing).esm
fook2.esp
(the fook2 DIK thing).esp
(the fook2 zeta thing).esp

again this is not necessarily the correct order, but its the one I use now, and I have like a bazillion other mods so, yeah.

I had a similar problem in the player house in megaton, cause tons of mods (including my own) modify that cell, and a conflict within that cell will prevent your game from saving and/or loading.
also, another thing you could try is turning off the auto saving, and leave megaton for awhile, sometimes that works for me.
Good luck!

Well fook2 isnt my only mod but the only one that effects megaton far as I know. my load order is:


[X] Fallout3.esm
[X] Anchorage.esm
[X] ThePitt.esm
[X] BrokenSteel.esm
[X] PointLookout.esm
[X] Zeta.esm
[X] Lings.esm
[ ] HairPack.esm
[X] CALIBR.esm
[X] FOOK2 - Main.esm
[X] FOOK2 - [DIK] DLC Improvement Kit.esm
[X] LingsFinerThings.esm
[X] DCInteriors_ComboEdition.esm
[X] AQFH.esm
[X] FOW - The Last Child of Gallifrey v2.esm
[X] norepairneededv2.esp
[X] DarNifiedUIF3.esp
[X] CASM.esp
[X] Alternate Start - Roleplayers.esp
[X] The Mantis Imperative - Mantis.esp
[X] The Mantis Imperative - Jello.esp
[X] The Librarian.esp
[X] AQFH_C_103.esp
[X] bzArmour.esp
[X] FOOK2 - Main.esp
[X] FOOK2 - [DIK] DLC Improvement Kit.esp
[X] FOOK2 - Mothership Zeta.esp
[X] FOOK2 Main [Hotfix].esp
[X] FOOK2 DIK [Hotfix].esp
[ ] Echo_UseBothGloves.esp
[X] HZ_M92SE.esp
[X] Gantz stuff.esp
[X] 3EFhelmlessstealthsuit.esp
[X] Ghostbodysuitv3.esp
[X] LingsPrettyThings.esp
[X] LingsPrettyThings-BrokenSteel.esp
[X] CRBSOR.esp
[X] Nano Alpha.esp
[X] player150%.esp
[X] ClassicCarryWeight.esp
[X] HZ_M92C-DSE_Professional-CALIBR.esp
[X] TheFingerOfGod.esp
[X] FOW - The Last Child of Gallifrey.esp
[X] cleo_adamantiumX.esp
[X] Starke's Enhancement Perks.esp
[X] NoLockTopic.esp
[X] HY_direwolf_type3.esp
[X] 1PipboyPDA.esp

So no one has any advice on what to try to get it working?