Can I install a device driver with only SYS file in Windows 7? No equivalent INF is available

I do not have an INF file of a network card device, but was only able to find a SYS file on the Windows 7 PC on which the hardware is installed and operable. Can I simply re-use the SYS file from this PC into a different PC to install the device driver for the network card device? Or I have to use an INF file every time I have to install the drivers? Please advise. Thanks.

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