Bit of a specific one but I'm planning on installing chrome os on a pc I have laying around, and wondered how it would deal with the way this pc handles accessing the internet (through a PCI - no express - internet card which attaches via ethernet). If it doesn't work, will usb WiFi adapters work either?
Chrome OS has Linux kernel, so it depends on what drivers are already built into the kernel. There is no "install driver" concept in Chrome. It applies to both wired Ethernet, and WiFi adapter (USB, PCI etc).
Why you want CHromeOS? It is just a souped-up browser, and if you think your 10-year old PC will fly, you'll be disappointed.
On top of that - there is no Google-sanctioned ChromeOS. Whatever you install on your PC named "Chrome OS" would be someone' side effort, with little to no support if you encounter issues.