Enable And Disable Controls Based On Selection In Previous Combo Box

[paul_pearson]

Hi

With the userform in the "Category" Combobox if "Internal" is selected then the "External" Combobox entries are not visible/cannot be selected...if Category "External" selected then "Internal" Combobox entries are not visible/cannot be selected....
Also with the above can the selections in all box`s in userform only be made in order.So a date must be entered first,machine second,Category third....etc..etc..if a box is selected before a entry is entered in any box above it then that box entries remain invisible until entries are entered in order starting at the very top....a message boxs opens saying entry must be made in Date,Machine,Category etc..etc..

Thanks

Paul