This is a huge question you are asking, and there will not be a 5-minute
answer for you.
The question boils down to:
a) How do you create a relational database to handle the 600 columns from
Excel, and
b) How do I populate the relational dataase with the existing data.
To answer the first question, you will need to gain some understanding of
the process of normalization: where and how to break this data down into a
series of one-to-many relationships. If you have never done this before, it
will involve a considerable amount of reading and experimenting to get it
right.
Here's a starting point, consisting of 8 PDFs that will get you started in
Access:
http://allenbrowne.com/casu-22.html
The 3rd one explains the normalization process.
Here's a couple of ultra-basic examples to get you started:
http://allenbrowne.com/casu-06.html
http://allenbrowne.com/casu-23.html
And here's a bunch more links dealing with this:
http://www.accessmvp.com/JConrad/accessjunkie/resources.html#DatabaseDesign101
Once you have a nice relational structure set up so the data is easily
queryable, you will have the advantages of using a database using a
spreadsheet, e.g. suitably typed fields (e.g. a Date/Time column where you
can't type invalid dates like you can in Excel), validation (e.g. certain
field marked as Required, so they can't just be left blank as they can in
Excel), and relational integrity between your tables. The second question
then becomes how to import the existing data from Excel.
Again, this not a simple process, because you will find the spreadsheet
contains bad data (such as "Not applicable" typed into a date column, or a
blank where the field you created in Access is required.) Importing existing
data into a good, relational structure can therefore be time-consuming,
depending on how bad the Excel data really is.
After you have a good relational structure, and the data imported, the next
stage of development involves creating the queries (to select, sort, and
combine the data from different tables), the forms (the interface for
entering/searching/editing/deleting data), and the reports (for outputing
results.)
Whether it is worth your time to create a relational database and import it
will depend on how important the data is to you, and whether Access really
is the best tool to manage it in. It may well be worth the effort, but you
need to be clear before you start as to what you are doing.
