Just after I copy the new map to my TT, my computer was down. when i reboot the computer, it can't connect to my TT. I tried pushed and hold the power on/off button on TT, it still kept on. Now i can't turn the TT off, and PC can't talk to it. What should i to do, please advise. Thank you.
Have you tried "resetting" your TomTom by inserting a paperclip into the very small hole on the botton / base of the TT.
Your owners manual will show you exactly where that is. If you have an SD memory card it is just near the insert hole...... it is small, about 1 millimetre and can easily be missed, it does normally say "Reset" .......( very small too ).
I once had a similar problem that would not allow a reset as I describe above, to solve that I removed my SD memory card, held the large TomTom turn on power button down whilst simultaneously holding in the TT "Reset" with a paperclip, I released the power button first and then withdrew the paperclip from the "Reset" hole. The TT then booted to main screen with TomTom image, I inserted the SD card when the screen flashed the blue animated "Insert SD" image....... all OK.
If would be very tempted to reformat your SD memory card and re-install the TT operating system ( called Navcores ) & copy across your maps, voices etc if youo have them.
If hope you made a back-up when you got your TT that would make things more simple once you achieve re-communication with the device via your PC.
If you re-establish communication with your TomTom but it will not recognise your "System" I would likewise be tempted to remove all files from your device, connect to "TomTom Home" software and allow it to put on a new "System" for you. When you reboot it should be clean. Obviously you will still need to copy onto your TT SD memory card your Maps & Voices and activate these if necessary.
I'm very new to TT & GPS systems and there are more experienced members who may have better advice and will assist if possible.