The reason you may not be finding a GPS signal could be any one of these : -Poor Weather -Undergound/In Tunnel/In Garage -Software is out of date -Device is broken The list of reasons above is ascending in order of seriousness. Poor weather can be waited out, Being underground/in tunnel/ or in a garage can be fixed easily by leaving that area, Software can be updated, however, if it is the device itself you will need to replace the entire motherboard because the GPS locator is not a peripheral device. Guides to do this are on this page TomTom VIA 1605TM Repair
The best way to know that it is a TomTom VIA 1605TM is to open the hatch at the top of the device where the memory card that holds the map is placed. The card will look like an SD card. It will say TomTom VIA 1605TM, if you can not find this marking, then you may not be working with a TomTom VIA 1605TM.
There are many reasons your screen could be black, try the following things (in order) : -Restarting your device -Using a different power source for your device -Using a different power cord for your device -Replacing the battery in your device -Replacing the screen in your device -Replacing the motherboard in your device As the list goes on the repair gets more and more serious and expensive so make sure to follow these in order! The repair guides and further information can be found on this page TomTom VIA 1605TM Repair
These simple steps should help you with your problem : 1. Follow this link to get started 2. Select your country of origin 3. click "get started" on the following page 4. Select "Download MyDrive Connect" on the next page (if you are using a mac, select the link below that!). 5. Run your downloaded program 6. Accept the licensing agreement 7. Click install to install MyDrive Connect 8. Congratulations, once you plug in your device you should be able to connect it with MyDrive Connect!