If you have an SD card installed then
Remove the SD card from the tomtom
Try the hard reset.
Push a Paper clip in the tiny hole by the card slot.
Push it in firmly whilst the unit is powered up (not too hard) for about 3 seconds then release.
You may have to power down and then up again and even hold down the power button a little longer the first time you do this.
That would normally reset the tomtom.
If it does then get the latest version of TOMTOM HOME
Install it and run the program.
Now with your GPS tunred off connect it to your computer via a short USB lead.
TTH will now start up and from there you can update the tomtom itself.
If you are getting a red cross whilst bootng the GPS then
The card may need to be formatted properly first or re-formatted.
Formatting is better done in a card reader.
There are differing views but this method has always worked for me.
Insert the card in the reader,. Using my computer or windows explorer
right click on it and select format
select FAT32 as the files system
Now connect the tomtom to the pc but don't let tomtom home run.
Exit TomTom Home if need be.
You now need to select your tom tom which will also show as a drive and may even show its own special icon.
In windows explorer select tools then folder options.
Click view and tick the box for "show hidden files and folders"
It may warn you but you can ignore it.
then just copy ALL the files from the tom tom to your sd card.
DO NOT USE CUT AND PASTE !