You can use the "upsizing wizard" to convert an access database to sql server. Once it has been converted, you can run update statements through a user interface called "query analyzer" or "enterprise manager" - query analyzer is preferred. Let me know if you have additional questions.
Think i have had the same problem as you are having. I found this web page which has been the most helpful up to now but im finding i have to get snippets of info here here and everywhere! seems to be coming along nicely now, so keep Persevering
Anyways heres the web link hope it helps:
Can you post the SQL that you are using so we can see what you are trying to do? A CREATE statement for your two tables, and INSERT statement for them, and the INNER JOIN that you are trying to do would be great.