When was Microsoft Windows first released?
Microsoft Windows version history
Windows 95 - original release
Windows 95 A - included Windows 95 OSR1 slipstreamed into the installation.
Windows 95 B - (OSR2) included several major enhancements, Internet Explorer (IE) 3.0 and full FAT32 file system support.
Windows 95 B USB - (OSR2.1) included basic USB support.
Windows 95C - (OSR2.5) included all the above features, plus IE 4.0. This was the last 95 version produced.