Windows 3.1 under Virtual PC
To get Windows 3.1 run on Microsoft Virtual PC, the necessary drivers for the hardware emulated by Virtual PC must be installed. Except for Sound Blaster 16, for which Windows 3.1 may already have the driver, other drivers must be downloaded and installed manually
Sound Blaster 16 (ISA Slot)
S3 video card (support up to 1024×768 screen resolution and 256 colors)
DEC Ethernet card
As for network connection, the following 2 components are needed:
TCP/IP stack
WinSock (copy and paste to C:Windows or C:WindowsSystem when prompted for missing DLL)
The last version of Internet Explorer that works on Windows 3.1 is Internet Explorer 5.0 16-bit edition.
Download all of the above here