TomTomGP 910 I just got this and did the install OK, but when I try to get a signal from my car, all I get is this big red X on the screen. I honestly don't see a reset button on this unit, or I would try that. Thanks.

Hummmm... the YELLOW RCA should be your VIDEO cable and have VIDEO signals.

Are you SURE your TV is set to the CORRECT "INPUT" SETTING? And DO YOU hear and audio>?

Anthony

http://www.tomtom.com/support/index.php?Language=1&query=red+cross&FID=1898

Red cross issue:
http://www.tomtom.com/support/index.php?Language=1&query=red+cross&FID=1898

Read this:
http://www.tomtom.com/support/index.php?Language=1&query=red+cross&FID=1898

I have seen the green screen problem a few times before and this was caused by corrupted data / software or an error in booting up.
If you can't turn any TomTom off then perform a reset by inserting a paper clip into the rest hole and give 1 short press of the reset button ( it's a tactile switch so you should feel it click ) then try switching the TomTom on again the normal way. ( reset buttons are normally found through a small hole underneath the TomTom ).
If the TomTom does switch on but continues as before with the loading up problem , then it's best to format and reload all files from your backup copy.
A RED CROSS indicated a loading fault / corrupted files / incomplete files / corrupted or damaged media . ( media , meaning SD card or hard-drive )

I discovered that there was a file on the 910 called CLMDATA which was corrupt. When I deleted this in Windows explorer, the unit started up and worked OK. This file is recreated when the unit starts up.

DO YOU HAVE TOM TOM HOME INSTALLED ON YOUR COMPUTER??

LET ME KNOW

I HAVE A 910 ALSO I CAN HELP YOU

plug the unit into computer and check for updates if it still has a red x after installing the up dates call tech support

had same problem/reloaded thru computer/ok till today ,won't turn on now

Tomtom GO 910 GPS Receiver flashing white X in a red circle
I discovered that there was a file on the 910 called CLMDATA which was corrupt. When I deleted this in Windows explorer, the unit started up and worked OK. This file is recreated when the unit starts up