is it a laptop or desktop? laptop use the back USB port for better result.

did you put the image .bin file into C:\program files\maemo\flasher?

download the image yet? download it and put in the flasher directory. Then go to run and type CMD. THen you follow the instruction.



1. put the .bin image file into C:\%ProgramFiles%\maemo\flasher-3.5\
2. make sure your phone battery is atleast halfway. Turn the phone off
3. Open Command line and type:

%ProgramFiles%\maemo\flasher-3.5\

4.Hold the u key on the keyboard of N900 and connect the USB cable at the same time
5. In the commandline run: flasher-3.5.exe -F RX-51_2009SE_3.2010.02-8.003_PR_COMBINED_003_ARM.bin -f -R

make sure you type the name correctly. Other wise it won't work.

You can try the flasher commands here:
http://wiki.maemo.org/Flasher