jaywhy

Hello all, I'm in a bit of a struggle as my sat nav (TomTom) on my 06 prodigy. it has been unable to detect any signals. At the bottom screen it just says no gps device. I tried all the options and everything. Does it have to do with the program? or does it have a problem with the antenna? Would downloading version 16 whereis maps help solve this problem? but the whereis maps is too big for the SD card to handle. Any ideas? :( greatly appreciated if u could help...