A service pack is a collection of updates, security patches, and fixes that are bundled together and released periodically by Microsoft. These service packs aim to improve the stability, security, and performance of the operating system. Windows 7 Service Pack 3 is the third major update package for Windows 7, which includes all the updates and fixes released since the second service pack (SP2).
Standard single-layer DVDs are 4.7GB. You need a dual-layer DVD (8.5GB) or an 8GB+ USB drive . --- Windows 7 Service Pack 3 Iso Download 64-bit Offline