macOS9 networking

I do not know why your PC card hangs when NIC is enabled. However, If you use PC Setup 1.6.4 or earlier, it will not support PC networking. The PC Network extension will not load when you boot the Mac, and it may cause your PC to hang when booting it. There are three solutions that may work. 1st - PC Setup 2.1.7 - You need it only on the Mac side, unless you need 32 bit support for your CD ROM. Download it free from www.pcsetup2x.com.
2nd - get the networking patch for PC Setup 1.6.4. It modifies PC Network extension so it will load.
3rd - use a resource editor to manually change the version number of the PC Network Extension so it will load. With any of these, your machine should boot OK, but networking may still be a problem. It looks like it works, but it cannot access most web pages or transfer large files. I solved mine by setting MaxMTU to 1492 in the registry.