Since you have said that your TomTom is only displaying a flashing cross (or "X"), it is because the TomTom application is not installed or can not be found. This usually happenes when you attempt to update your unit and it is interrupted (i.e., not properly disconnected from the computer, the TomTom was underpowered by using a USB port on your monitor/keyboard, or lost power during the update. In fact, it might just be pissy.)
Down to how to fix it: You essentially just need to reinstall the application.
1. Soft reset (I know you have already done this but am providing a link just in case: http://uk.support.tomtom.com/cgi-bin/tomtom_uk.cfg/php/enduser/popup_adp.php?&p_faqid=6965
2. Connect you’re GPS unit to your computer
3. Press the power button for about 5 seconds and the TomTom Home will start.
NOTE: It is highly recommended that you use TomTom HOME to make a backup. You can find out how to do this here: http://uk.support.tomtom.com/cgi-bin/tomtom_uk.cfg/php/enduser/std_adp.php?p_faqid=3171&Lid=1
4. Delete application files (so we can do a clean install), to do this:
- in HOME, click "MANAGE MY NAVIGATION DEVICE"
- Select the ITEMS ON DEVICE tab and tick the box by "APPLICATIONS".
- Then click REMOVE ITEMS FROM DEVICE
- A warning will pop-up, click "OK"
- Select the ITEMS ON COMPUTER tab and tick the box by APPLICATIONS
- Then click REMOVE ITEMS FROM COMPUTER
- Another warning will pop-up, click "OK"
5. Reinstall the TomTom Application by clicking UPDATE MY DEVICE
- Then click UPDATE AND INSTALL
- Once done, click DEVICE > DISCONNECT DEVICE
6. Next, we're going to run the TomTom Clear Flash Tool (the downloads include step-by-step directions for clearing the flash)
- for windows: http://www.tomtom.com/updates/clear_flash/clear_flash.exe
- for mac: http://www.tomtom.com/updates/clear_flash/clear_flash.dmg
7. Safely disconnect.
- on windows: click the SAFELY REMOVE HARDWARE ICON (a icon with a green arrow that is hanging out in the system tray and then choose "USB MASS STORAGE DEVICE" from the pop-up
-on a mac: drag the desktop icon of your device to your trash.
8. Your device should start up automatically. If it hasn't within 10-15 seconds, press the on/off button.
If by chance this still doesn’t work, you can try formatting the internal memory or memory card of your TomTom. If you need a link or directions, simply send me a message or reply!
Hope this helps!