1st - Try a different USB cable, sometimes the cables look good but are bad.
2nd - Isolate the issue - Try the Line 6 on a different machine and see if it works there.
Let me know the exact process you are following to install the drivers, I am assuming you got a disk from Line6 to Install....if so, try not using it and get the software off their site, chances are your CD has old software than on the site.
Check for any patches that your Line 6 needs before installation, there may be bugs in the software you are trying to install.
It may also be an issue with the USB Drivers on your PC, could you let me know which OS are you using? XP? Win7? If it is Vista, I would suggest you dump that OS first before trying to use it for anything.....I seriously mean it.
Go to your PC manufacturer' site and download the latest chipset drivers for your PC, if it is not branded, search through the Device Manager (Right Click on My Computer > Properties > Device Manager) and check for the USB details.
Always maintaining the latest drivers would help a ton.
Hope this helps.....if all else fails, and you know the POD works on another machine fine, then the bramha astra - Format that PC with a fresh install....of whatever OS you like (I would never Install Vista on mine)
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