Need help setting a date to a macro and changing the filepath using a different cell

Hello!

Just joined the forums today and was wondering if anybody could help. I have two questions. My first question is that i want to make a macro where if I click on it it will prompt me to enter in a date and will paste it in say... cell a1.

My second question is, how do i make a file path onto an excel file and change a specific cell which will change the file path. An example of this is if in cell a1 the date is 20110425 i want the cell path in cell a2 to change to P:\fin_all\fin_all_20110425.csv. And that once this changes I should be able to click on this file path and should open the file.

Many thanks in advance!