There is a grid of lines in my lcd screen

The Display button toggles the information shown on the LCD (or turns it off entirely). Make sure you haven't inadvertently pressed it and turned off the display. It works as follows:

Press once for Normal view in LCD viewfinder
Press twice to turn on Rule of Thirds grid lines
Press three times to turn off LCD display
Press and hold 1 sec. to decrease/increase LCD brightness

trouble shoot your camera to fix its problemand return optio to working order.

Hi,

The frame lines in the Camera may be the Grid Line option. This option can be disabled in the Camera. Follow the steps mentioned below to resolve the issue.
Set the Camera to Shooting mode.
Select the MENU then, (Settings) --> (Shooting Settings) --> Grid Line --> OFF.

This should resolve the issue.

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This sounds like it might be a defective CCD imager. If so, Canon should fix this for you for free worldwide, and may also include free shipping both ways (free shipping varies with countries). This is regardless of your camera's warranty status. Please check this link for more info.
Applicable cameras include:
A40, A60, A70, A75, A80, A85, A95, A300, A310, S1 IS, S60, S200, S230, S330, S400, S410, S500, SD100, SD110, IXUS V2/V3/300/400/430/500/II/IIs, IXY Digital 200a/300a/320/400/450/500/30/30a

Press DISP. button, and repeat untill the display shows up

Hopefully you resolved this already. If not, push the "DISP." button left of the MENU button. Pushing it gives you three options: black (for discreet shooting so your LCD doesn't give garner dirty looks from fellow concert goers), liveview, and liveview with info overlayed (shooting mode, ISO, etc.). Good luck!

The Display button manually turns the LCD display on or off to save batteries. If you accidentally had turned the LCD off, It should only take one press of the button to turn it back on and leave it that way. As such, it's not you but the camera. The A570 IS is relatively new. Your camera is likely still under warranty. If so, contact Canon for warranty repair (see the following link):

http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&keycode=2113&fcategoryid=221&modelid=14905

The camera has a mirror lock up feature for cleaning the CCD sensor. You may have engaged it. Check your manual about this function

Your lens is Damage. Prevent nextime from sunlight , it damage your lens if not in use.

It seems that you have been selecting Panoram view to shoot photos. Go to menu and change the image options and select SHQ or whatever and not panorama. This should solve the problem. Panorama view shows the grid lines all over the screen and it is meant for taking 360 degree panoramic views.