There have been 12 relevant hotfix updates (the 13th update applies only if you are running Mac OSX Mavericks) released for CF10, plus a mandatory update to fix security certificate issues with the updater. Many of the updates affect integration issues with IIS (it sounds like you are running on Windows). I would suggest installing the mandatory updater per Adobe's instructions, then installing the latest update (which for Windows would be hotfix 12). The hotfixes are cumulative, so you don't have to install each of them - the latest will do. Also, make sure that after you install the update you rebuild the IIS connectors per Adobe's instructions.
As for memory, if you are running SQL Server alongside ColdFusion on the same box, I'd suggest at least 6-8 GB RAM (2 for the OS, 2 for SQL Server Express, and 2-4 for ColdFusion). If possible, I'd run the 64-bit version of ColdFusion so you can allocate more memory to the JVM.
Thank you, Carl!
I also found, thanks to another forum item, that the virtual directories of CFIDE and jakarta need to be present on every website, otherwise that 404 error comes shining through. That also helped a lot of my issues.
I'll look into these updates now.