There are two downloads available for Windows users.
Note: the Windows EXE requires a MSVCR100.dll to run. Most computers will already have this file and in the Windows PATH. However, if the first copy of the file found by the EXE is a 32-bit copy of the DLL, then SQL Developer will fail to start. You can fix this by copying a 64-bit version of the DLL into the BIN directory or updating your OS PATH such that a 64 bit copy of the DLL is found first.
If SQL Developer cannot find Java on your machine, it will prompt you for the path for a JDK home. This only occurs the first time you launch SQL Developer. A valid Java Home on Windows will be similar to