Ihave a lowrance globalmap 5150c which appears to be stuck on the waypoint page. There is no colour on the page and i want to get the gps back to the colour map page with the cursor

Only from the maker, or a somewhere like here
https://www.sparesmarine.co.uk/webshop/electronics/globalmap-3500c/lowrance-globalmap-3500c-spares-accessories/?brandFilter=Lowrance%20GPS%20Chartplotter

Help & Support ' Fishing Electronics ' Lowrance USA ...

www.lowrance.com > help-and-support > guideTitle=Gl...

home. share. GlobalMap 3500C Unit and Accessories Information. language. mail_outline. link. GlobalMap 3500C ... 101-99. Flush Mount Kit. FM-5. 113-04.

This is a common problem with Lowrance products. Unfortunately they only service their product for seven years after prduction date. You might check with lowrance to see if you can get the unit serviced but most likely you will need to replace the unit.

The backlight is failing.

Hi!

Here's the link for your Owner's Manual!

http://www.lowrance.com/upload/Lowrance/Documents/Manuals/GM100.pdf

Hope this helps.

Try this hard reset procedure: (warning: this procedure will erase all waypoints that have been saved)

1. Turn unit off
2. Press and hold the ZIN, ZOUT, and PWR keys at the same time.
3. Release the ZIN, ZOUT, and PWR keys once the alarm "warning, do not rely..." appears.

The unit should now be out of demo mode.

You can try a hard reset:

1. Turn unit off
2. Press and hold ZIN, ZOUT, and PWR until you get the "WARNING, DO NOT RELY..." message.

If that doesn't work, try installing the latest updates from http://www.lowrance.com/en/Downloads/Product-Software-Updates/

If it still doesn't work, and you can't get through to Lowrance by phone, try emailing them by going to http://www.lowrance.com/en/Support/Product-Support/Contact/

It probably won't be worth repairing the unit. You will be better off putting that money into a current unit which will be much better than the 2400 and probably less expensive than the 2400 was when it was new.

upgrade it firmware usnig the download support are in the main page of ur product u will find it there!!

The screen is the weak point of the 2000's.  I have one myself, and without warning a number of "lines" appeared on the screen, getting progressively worse over time.  
Perusing other forums, it seems we're not alone.  Unfortunately the only "solution" I've found thus far is to purchase a new head unit (eBay is a terrific source!).

I've had great success locating full user manuals for the Lowrance products at:
http://primus.lowrance.com/support/resultDisplay.do?gotoLink=6&docType=1000&contextId=857%3A6.21%2C1808.1840%2C6.21&clusterName=ClusterPublic&lang=english&docset=%2FDocuments%2FUnits%2FLowrance%2FGPS&contentId=32918bdd-e14e-42de-8bf0-81e9cb11ab7e&responseId=135ccbe2cfd4f608%3Adcb03b%3A11a44cb2b51%3A5f29&groupId=4&answerGroup=1&score=480&page=http%3A%2F%2Fprimus.lowrance.com%2Ficr%2Funits%2FLowrance%2FGPS%2FGM4800Mpub.htm&result=1&excerpt=GlobalMap+4800M&question=lowrance+4800&resultType=5000#Goto6

If that URL doesn't work, please visit Lowrance.com, and select self-service support.  Click the "Product Information" link on the left side of the screen then enter your product name in the supplied field.  You should be able to find any information on the GPS you have!