Hi @Hyper3232, thanks for checking in with us on the Dropbox Community!
In general, if you don't want:
Your desktop app to sync temporarily, you can quit/exit Dropbox. In this case though, you won't need to sign back in using your credentials.
Your computer to be linked to your account and use your credentials to sign back in, you can unlink it. However, please keep in mind that if you're on a Basic account, you have a three device limit. You can read this article for more info.
However, please bear in mind that when you install the desktop app, a Dropbox folder gets created on your computer.
Even if you temporarily stop the desktop app from running, unlink your device, or completely uninstall, that Dropbox folder stays on your computer, doesn't sync online, and becomes a regular folder just like any other.
I hope this information helps, but let me know if you have any other questions. Thanks!