Gateway 450ROG screen went dark

You must go through the safe mode and uninstall your graphics driver and install another one, may be you will find more compatible driver with your graphics card and your windows copy on gateway website.

check ribon cable by taking laptop apart and makign sure its conected to board correctly, but more than likely new bulb or replacement screen , search ebay they have a tone of secound hand screens for decent prices, search gateway 450rog lcd displays, hope this helps in some way

Review your user accounts, you may need to clean the registry. I reccomend CCleaner it;s open source and its pretty solid and best of all it's free

Taken apart, looking for abnormal solder etc checked powers switches decided that this unit was acting like it may have shut down due to excessive heat issue. pulled battery on board, tested ok, re-installed everything and found that this unit now is active. Conclusion: I suspect the bios shut this unit down, hard reset correct this issue.

it may be over heating !!
turn it on and run it till you hear the fan turn on, then check if there is much air coming out of it.
if not use a vacuum to **** air throw it as you blow hard into the slot that the air should come out of

I'm betting that you need a new "Inverter" board, especially if it's a Gateway 450ROG.
There is an inverter that Gateway used in several models that has a known defect.
Inverters are relatively inexpensive ,and easy to replace. You could ven do it yourself if you have a little skill at disassembly / re-assembly. Tell me the model number of your laptop and I can help you more

You can go here and update your video and all other drivers
http://www-307.ibm.com/pc/support/site.wss/MIGR-67100.html

Try hooking the Laptop to an external monitor like from your desktop pc,,you can see the connection on the back of the laptop,,When you do this, and you can see Windows on the Desktop monitor,,then this would indicate that your Back light on your Laptop screen may have burnt out .

the screen is not a sealed unit... and the backlight and the lcd bulb can both be changed out...
I do it on a daily basis....

It is way cheaper to change out the lcd bulb than it is to replace the lcd display panel... Way CHEAPER

the results are the same

Without a visual inspection it would be impossible to say. But it does sound like you will almost certainly need a new motherboard.