Scott,
Start making a backup of all your known files. If you are confident of reinstall all your applications, reformat your hdd and reinstall everything. Try to avoid using too many third party utilities. It will give you more confusion than solving the problem. As a Desktop Support Engineer for many years, most of the problem I've encountered are between the keyboard and the chair. If you can afford to have 2 computers, I know you can, get a dedicated one for internet use and one for your home music production. Internet is the place where you can catch all those anomalies going on your systems.

Dan