navigator 3 to 5

having upgraded from 3 to 5 I now find my 512Mb storage card nearly full which dir.can I delete
2 great britian dirs
msmetadata
tomtom gps
tomtom nav
tomtom nav
zip
Think this is making my dell x30 work slow

You might be better off copying your files to a PC, deleting everything off your mem card and reinstalling. This way, if you get any problems, you've got the files still on your PC