I'm not going to answer your question straightaway but I am going to point out that Google's latest cache of your site :

http://64.233.161.104/search?q=cache:6cSMEhHpcaEJ:www.adamsweb.us/blog/+adamsweb.us&hl=en

shows you running b2evolution 0.9.0.10, which is not the most current release.

Now to answer your question -- you go download the MOST current release AND THE xml-rpc patch, and you upload all the files where they need to go, making sure to preserve your original _config.php.

1) The installation file says to overwrite the old files. Do I just save the old _config.php file.

2) It says to back up my database. What file is my database? Is that where the blog posts themselves are stored?

Thanks,
Adam Graham

1. yes
2. your database is intact

Upload all the files except the _config.php.. In fact, to be safe, I would delete ALL of the existing b2evo files except for _config.php.

You do NOT need to run the install again