Looks like he's helped us out .. I'm seeing XL330 now.
To the OP ..
I am guessing it has been a very long time since anyone has used this unit.
First, please make a backup of your unit per this link >>>
https://www.tomtomforums.com/t17864-how-backup-contents-your-unit-computer-how-restore.html
Having done that, download and install the utility at this link. This utility is used to talk to your TomTom and update it. >>>
http://www.tomtom.com/services/service.php?id=16&tab=87
Plug your unit in to your PC's USB port with an appropriate (USB-A to USB-MiniB cable, readily available) and turn it on, and for the moment, just ignore the Home application when it fires up (connection of the unit should cause Home to auto-start) and any updates that it is recommending to you. We'll get to that in a minute.
Using your PC, and looking at the TomTom as an external disk drive, delete of the content inside the "ephem" folder, but not the folder itself,
on your XL unit.
Now, using Home, perform a proper USB disconnect of your XL ("Device / Disconnect Device" from the tab at the top, or just use the blue arrow in the lower right corner) . Then shut down the Home application.
Disconnect your XL from your PC, and plug it in again, allowing Home to start up again. At this point, Home will be asking to update your unit with several things, not least of which is new GPS QuickFix data. After the update is completed, properly disconnect your unit again.
Now, pretend you are starting up the unit, but continue to hold down the power button until you see the TomTom logo and hear the 'drum' beat. It will take about 20 seconds from the time you start holding down the button. Immediately release the button when you hear the drums start. This resets the unit.
Now, get the out in open sky and turned on for at least 12-1/2 minutes. It might not take that long, but that's the maximum it should take. See how it does then.