I have never had a problem and then I went to use it and the screen has a bunch of colour lines thru it and you can read some of it but not enuf to use it.

Hi, Please check the following.

1. Either the cable that connects the screen to the main circuit board has dirty contacts.
2. Perhaps the conenctor on the screen cable has become loose due to a jolting of the tomtom.
3. I have seen very similar problem on tomtom's before caused due to corrupted data on the SD card. This might seem an unusual and almost impossible simptom but I have see it several times. Try reinstalling the software from a backup you made earlier .