Userform Woes

I HAVE DESIGNED A USERFORM FOR MY DATABASE BECAUSE IT WAS SO EASY TO MESS WITH THE SHEETS
My userform has quite a few controls on it and it does what i want ....err that is most of the time
on starting the form i use the comboboxes to select the items i need and the buttons are self explanitory now this works fine ..for a while then all of a sudden formula's disappear even though they are protected then a button stops working the formula's that go missing are the ones linked to the form or controls on the form.
today for some unknown reason (to me anyway) excel crashed and restarted but it said that all activex controls were lost but had been repaired but when i started the program there was no forms at all so ...luckily i had a backup to use
originally all the macros were in modules with call routines from the form and now i have put all the macro's on the form right /wrong i dont know
I have been working on this database for the past 3 months it originally grew as big a 9mb but i have cut out a load of un needed stuff and its now down to 1.5mb all the little niggles are starting to get me down i have put a pic to show form ...maybe theres to much on there maybe someone can tell if that is so.......maybe if i put all the macro's on 1 module some one can take a look and tell me whats wrong
if anyone wants anything else dont hesitate to ask


thanks in advance


john