Using the Module Loader to uninstall is the recommended process. Just follow the prompts. We recommend not removing tables during that process just in case they are needed later.
However, there are times when this process will not work and it greatly depends on your server environment. If something goes wrong and your CRM comes back with a white screen then follow these steps. We recommend doing Step 1 before uninstalling to minimize downtime, just in case.
1) Grab a clean instance of your CRM version. If you are using SuiteCRM then SourceForge is a great place to grab this.
2) Back up your production CRM files (copy to another directory)
3) Copy the following directories from your clean CRM instance into your production instance:
/data /include /modules /soap /themes
4) Log in and run the following three repair steps:
Admin -> Repair -> Quick Repair & Rebuild Admin -> Repair -> Rebuild Relationships Admin -> Repair -> Repair Roles
You should be up and running at this point.