f20 says connect to usb but wont show in my computer

[ataxy]

well i guess the title says it all the last time i had update rockbox was on my previous laptop now i am trying to update it but it wont show up in my computer the gigabeat screen shows that its connected true usb but my computer does not show me that a new drive is connected
current version is r18162-080730

[Febs]

Are you connected to the USB port on the player or on the dock?  (You should use the one on the player.)

What operating system are you using on your computer?

[ataxy]

yes on the player

win xp pro

edit: ok dont know why but after plugging it and unpluging 20 time it now work!?!?!?!?!? but i really dont know why it now work, i have not restarted the computer or nothing it just worked