I understand you're looking for for Windows 10. However, I need to give you some important context before providing a direct download.

For standard 8051 development, users typically download the package: Keil Product Downloads

owned by Arm (acquired Keil in 2005). You cannot legally download a "full" version for free unless:

: If you have a valid Product Serial Number (PSN) or License Code (LIC) , enter it on the Product Download page to access previous versions, including µVision 3.

uVision 3 is primarily used for 8051, 251, and older ARM7/ARM9 microcontrollers.

: Most developers use µVision 5 (which runs natively on Windows 10) to open and debug code originally written in µVision 3. Installation Steps (General)