************* UPDATE **************
The advice here is outdated. MIDI support is being slowly eroded as new versions of Windows comes out. Do try the generic USB cables you see on Ebay as they are cheap enough to experiment with. You'll be able to work fine with one USB cable. Using multiple will probably give you trouble.
OS bit architecture apparently makes a difference. The 32-bit (x86) versions of Windows 7 and Vista appear to be more compatible and give less problems as their 64-bit counterparts for this specific purpose. For Windows 7 in particular, the 32-bit version still supports 16-bit compatibility mode. You may still be able to run most of the old tools found in this website's MT-32 section.
Slowly but surely new generations of generic USB cables are starting to appear with updated chipsets that support newer systems. Make sure that the ebay description says the cable supports the 64-bit version of Windows 7.
************* UPDATE **************
So you bought one of those cheap ebay USB MIDI cables and it's not working on Windows 7? Don't throw it away just yet. Download the file below and extract its contents to a place in your computer:
http://www.mediafire.com/file/fgq03z3l4w3j1dl/generic-usb-midi-driver.zipNow open up Device Manager and look for the USB MIDI device with a yellow icon next to it. Right click on it and choose the 'Update Driver' option. Tell Windows you will "Browse my computer." Choose "Let me pick from a list of devices" and then choose "Have Disk." Click on "Browse" and navigate to where you extracted the driver files. Select the file "emuxmidi.inf" and click on Open then OK then Next. If you get a warning message just say Yes (or Next) and let windows install the new drivers. You should see a brief progress bar and eventually be able to close the installation wizard.
With a little bit of luck your USB MIDI adapter should now be recognized and functioning properly.
