I have Ubuntu 7.04 on a Dell GX150 and installed a Syba USB2 PCI card to get USB2's as the GX150 only has USB1.1's. The card uses an NEC D720101 chip. There are no drivers for Linux with the card,nor on Syba's site. Connecting an external HDD to the card shows that power is getting through as the drive spins up, but the OS doesn't list (recognise) the drive. I am new at this, and this is the first hardware compatibility issue I have struck.I have checked through this site without finding the answer,can anyone help please?

Probably the module to use the USB 2.0 chip is not loaded. The module for it is either ehci or ehci-hcd or ohci.

To find what modules are loaded type lsmod in a terminal.
I currently have these loaded:
sg, sd_mod, usb_storage, sr_mod, sbp2, usbhid, ehci_hcd, uhci_hcd, usbcore, scsi_mod
and everything USB is working perfectly.

If you are missing some you can sudo modprobe modulename to get them loaded. Then try plugging in your disk again. You should get a dialog box asking what to do with the disk.
I am a bit surprised that ubuntu hasn't noticed your new hardware and installed the modules for you. /var/log/messages may show you some helpful errors. It is a long file, so scroll down to the end and read the last 1000 lines or so. It'll tell you what happened during the boot process, and may have extra information about your disk after you have plugged it in.

If yours is a brand-new install, and you are a complete newbie, it might be easier for you to reinstall, with your new hardware connected, it should then be recognised.
But we all had to start somewhere, and poking about with modules is where many of us took our first linux steps. Was I confused then? You bet. But confusion doesn't last that long

Many thanks for your help, when I return home I shall I shall try what you have both suggested; the commands to use at the terminal level are my present difficulty. Yes, poking about with modules will provide me with the more proficiency, no I don't need to do a complete re-install, my laptop has Ubuntu704 on it too, I use the GX150 for finding my way in Linux.

Many thanks for your help with the above problem. The GX150 now has usable USB2's on it that run about 150Mb/s as they should. I ended up loading the modules that you mentioned that I did not have loaded, so I am not sure which have fixed the problem! How does one find what a module does, or a listing of modules? man or whatis doesn't achieve this.

Pleased it worked.
I'm not sure. modinfo modulename supplies some information on each module, and google is helpful too.