To get it to charge from your computer, you need to select Data Transfer Mode when you first plug it in otherwise it won't charge. I had the same problem and checked on the Garmin.com web page's knowledge base for the answer. I have Windows 10 so I can't help you on the Windows 7 question. You may have to manually enter your device's information into Garmin Express. If that doesn't work, contact Garmin's customer service by phone.