Fresh install on Windows 7 64bit. No Mods installed yet except for all official DLC. My hands keep disappearing and reappearing. I dont get the dreaded red box with exclamation point in it or anything, they just disappear like someone cut my toons hands off. I have searched the net, googled it and have spent 4 hours only coming up with the "broken knuckles" and/or "deathclaw hands" bug results. It happens, then when in third person if I run forward, it sometimes fixes itself and my hands reappear. I am really at a loss and cannot for the life of me figure out what could possibly be going on. I have toggled Archive Inval. off/on and have not yet installed any mods. I have installed FOMM, FNVEdit, NVSE and the FNV4gb enabler in preparation to play again for the first time in over a year and this is what welcomes me within 3 minutes of playing. It begins while in Doc Mitchells house and continues even after I leave. Doesnt seem to matter what armor I am wearing or even in my undewear. Am at my whits end, has anyone seen this or know about such an issue or at least point me in the right direction? Please, please, please....I really want to play again. Thanks in advance for any help/tips.

Wanted to report back to you all in case you ever have this problem, I have fixed my one and only issue. For me, and I was warned with performance mods that mileage may vary from machine to machine, the issue of the strange dissapearing fingers/hands was in my case the 4gb Enabler. On my fairly powerful and newly built machine running the faked fullcreen and stutter remover was enough performance gain to not have any issues. I guess I over-performancified my FNV. I suppose I may have missed the part in the modding tutorials about "on a heavily modded game" that these all help. Thats obviously heavier than the 40 to 50 mods I run. So anyways, that was my issue with the disappearing knuckles/fingers. Removing the FNV4gb enabler has fixed my issue.

Nevermind. After a good few days of playing, my hands meshes are all broken again. I give up.

You have mods installed now?

I would disable anything you have and try vanilla.
Remove NVSE stuff and performance mods. Uncheck ALL mods you can keep DLC checked.
Disable archive invalidated. Backup then delete fallout.ini and falloutprefs.ini in your saves folder.
Start the launcher (the .ini will be remade) and try it.

post a dxdiag too: http://www.gamesas.com/topic/1122570-how-to-dxdiag/
Paste dxdiag between spoiler tags -> ... (replace the < > with [ ] on both tags)

Run a game cache verify couldnt hurt either:
1) Open Steam
2) Right click on Fallout: New Vegas
3) Hit Properties
4) Click the "Local Files" tab
5) Click on "Verify Integrity of Game Cache"

Thank you for your reply on this Jasper. I have discovered my problem has nothing to do with my game or install at all and looks to be an Nvidia problem. On my other machine with Ati SLI, I dont have any issues at all so Im playing again, just not on my newer Nvidia machine. And yeah, I did a fresh install after cleaning out registry with no mods, no utilities and played it vanilla and it did it then also. My brother in law who is something of a computer wiz had looked at it for me and looks like an issue between Nvidia phyisics and this game for some reason. What we see in game is that my hands are not cut in half, its like when my toon stands on certain places and my feet actually "sink down" into the ground like an inch or two, its like my fingers get jammed up into the toons wrist. It only happens when the soles of his feet are not above ground, so its very sporadic. Like the fingers know what distance they should be from the ground but the body doesnt. Its very strange. Anyways, I dont know if any of that made any kind of sense, since switching machines actually allows me to play, fully modded without crashing. I am still trying to read up on issues with this Gamebyro engine and Nvidia drivers trying to educate myself since the Nvidia machine is new and way more powerful. Again, my thanks for your response.