Find & Amend/Edit Data Via Userform

A.) As a user is entering data into a userform two specific values need to be checked in the existing data sheet.

Textbox1 ( date)
Combobox (operation name) {4 tabs on from textbox1)

They relate to the data stored in columns 'A' and 'E' respectivly.

What I'd like is, as the user exits combobox4 to check if the values already exist. If they do; fill the coresponding textboxes with those values and allow the user to make any amendments, then have it SAVE to the SAME row, would a record number be necessary to accomplish this?

B.) For a future development, Im thinking of applying the same principle to a different project, where 3 values need checking.

Textbox9000 (date) Column 'A'
ComboBox1002 (Staff member) Column 'B'
Combobox1003 (operation name) Column 'C'

Possible complications are that below combobox1003 there will be 12 other comboboxes(a value title, from column header) with associated textboxes alongside(value previously entered by user).

There will be 22 possible values for the comboboxes(the values will be the same column headers) The user will only ever have the choice of making 12 entries though.

Does any one have any spare code laying round for this one..