How to use a userform textbox to control a form

[counihan3]

I have been trying to figure out how to use a text form to drive what a userform does. My goal is when the key identifier is placed in the text box that in some way that number will be checked against all other entries, if a matching value is found the the userform will go to tab A if it is not found then the userform will go to tab B. How do I go about doing this. Also I have another problem, regardless of what tab is active all fields on it must be completed. I have run into the problem in my current userform that if I fill out tab A it still wants me to fill out tab B even though it is not relevant.