Too many columns
If you compact and repair the database you should be able to add columns again up to 255.
However, I agree with the comments above that you may have to review your
design.
Good luck.
What is the question?
Wile I agree with the posts above there is something I like to add.
I have noticed that frequently people are not able to explain in clear language what their problem is. I read the question several times and I still don't understand what they mean. Sometimes another user...
Tab Color
Don't know RGB but try ColorCop, a handy freeware program that gives
you the color info on any item on the screen.
Here's the link:
http://www.prall.net/
Good Luck
Combobox
Check out this link:
http://www.utterangel.com/pages/access_downloads.aspx
You can download an example called 'Combobox - Populate a Form'
that shows you how to do it.
Good Luck
Buttons
Open the Tool Box, make sure the Wizard is selected and drag the
button control onto the form.
The wizard will guide you through the process.
PS. Please next time post your question in the right forum. :)
Good Luck
Combo Box
It doesn't work because the necessary code in the After Update Event
of the Combo Box is missing.
Check out this link:
http://allenbrowne.com/ser-03.html
Or search this forum, there are many good examples around
Calculations
If you search the Forum you will find plenty of information about calculations
and how to implement them, as well as tips about importing spreadsheets.