I created an account solely to ask this question, and it might've been asked before.
I can tell that BOINC is installed on my SSD (C:), but I'd like it to store data on my HDD (D:). How can I change this? Do I need to let my current projects finish up, then reinstall?

During installation you can go into advanced options during installation and specify a different location. I have only ever installed the Windows version using WINE on Linux so I can't remember the exact wording you get.

Exit BOINC (BOINC Manager->File->Exit BOINC Manager->check "Stop running tasks when exiting the BOINC Manager"->OK)
Navigate to your BOINC Data directory (default in Windows a hidden directory at C:\Programdata\BOINC), then go up one folder so you can copy the BOINC folder.
Copy the BOINC folder to a folder on your D: drive (e.g. D:\BOINC)
Uninstall BOINC.
Reinstall BOINC.
In the third screen of the installer, click Advanced.
Change the path for the Data Directory from C:\Programdata\BOINC to D:\BOINC (or wherever you copied the directory to).
Continue installing BOINC.
Start BOINC Manager (Start->All Programs->BOINC->BOINC Manager)

We do it this way and not via the registry to make sure that all permissions on the new BOINC folder are set correctly.
If you miss the installer of BOINC, you can get 7.14.2 from here.
If you have trouble uninstalling or reinstalling BOINC, use the Microsoft Windows Program Uninstaller.

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