I need help my when i got the GECK it was working find and now when ever i hit the save button it shuts it down completely and it doesn't save any thing i need help from a few people with this.

Close all background applications, patch your GECK to 1.5, and start hoping.

I've never heard of this one.

Just a thouhgt - After doing the above stuff, try deleting your Geckcustom.ini and GeckPrefs.ini in your My Documents
My games\Fallout3 folder. Then load the geck up again. It will make new defaults of these files. Again, just a shot in the dark.

Start a 'new' mod and try to save it. Just make a simple change to something, like the damage a weapon does.

If it saves fine, then the problem is with the mod you are editing. If it has become corrupt, or a required BSA or ESM is now missing, or you did something that the GECK does not like, then it may crash on you.
Also, if you have Vista or Win7 and you installed your game in the default folder, and your not running as administrator on the GECK, it might crash on attempting to save.

all of your suggestions and it still doesn't work it was working fine but now i don't know what is going on with it. I do thank all of you for your help though.

Have you tried uninsatlling and re-insatlling it?

yes multiply times and nothing.

Have you done a virus scan recently? I'll admit, I haven't heard of this issue before, so maybe the problem is external to the Geck?