Windows 7 requires a specific 32-bit or 64-bit version of the driver depending on your system configuration.
Be wary of any website that asks you to download a "Driver Downloader Tool" or a "Driver Manager." You should only download .exe or .zip files directly. Never download an .exe that claims to scan your computer for drivers; these are almost always scams. Canon F151 300 Printer Driver for Windows 7
Your first and safest stop should always be the official Canon Support website. Windows 7 requires a specific 32-bit or 64-bit
f151_300_win7_64_1.0.exe