The LCD Monitor of my Canon PowerShot A95 shows purple, white, and black horizontal lines instead of a clear image of what is in the Viewfinder

This is known problem of ccd imager chip failure in Canon A95 camera, ccd imager chip will be replaced to get clear picture. It was coincidence that problem occurred at same time when you did some settings but it is not setting problem.
Canon offers free of cost ccd imager replacement.
Click Canon CCD Imager Advisory for details.

This sounds like it might be a defective CCD imager, and is a known defect for your particular model camera.. If so, Canon should fix this for you for free if you live in the US, Canada, and a select few other countries. If you live outside the US, contact Canon support for your country to see if they'll still honor the advisory (some still will, especially if you stress you knowledge that this is a known defect of the camera). They may also include free shipping both ways (free shipping varies with countries). This is regardless of your camera's warranty status. Please see this link for more info.

Affected cameras with this problem include: A60, A70, A75, A80, A85, A95, A300, A310, S1 IS, S60, S230, S400, S410, S500, SD100, SD110, IXUS V2/V3/300/400/430/500/II/IIs, IXY Digital 200a/300a/320/400/450/500/30/30a

See this FixYa link.

Oh my goodness, don't disassemble and don't go banging your A95's up for this problem. Sorry I missed this post when you first submitted it.

This sounds like it might a defective CCD imager. If so, Canon should FIX THIS FOR YOU FOR FREE, including FREE SHIPPING both ways. This is regardless of your camera's warranty status. Please check the following two links for more info:
　
http://camerarepair.blogspot.com/2007/11/canon-digital-cameras-showing-black.html
　
http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=225&modelid=13390&keycode=2112&id=29819
　
Applicable cameras include:
A40, A60, A70, A75, A80, A85, A95, A300, A310, S1 IS, S60, S200, S230, S330, S400, S410, S500, SD100, SD110, IXUS V2/300/400/430/500, IXY Digital 200a/300a/400/450/500

If it is Canon A95 camera then it has problem of bad ccd Image and needs to be replaced that part.
Canon will repair A95 for bad ccd Imager problem free of cost.
Please click Canon ccd Imager advisory for details.

This sounds like it might be a defective CCD imager. If so, Canon should fix this for you for free, including free shipping both ways. This is regardless of your camera's warranty status. Please check the following two links for more info:

http://camerarepair.blogspot.com/2007/11/canon-digital-cameras-showing-black.html

http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=225&modelid=13390&keycode=2112&id=29819

Applicable cameras include:
A40, A60, A70, A75, A80, A85, A95, A300, A310, S1 IS, S60, S200, S230, S330, S400, S410, S500, SD100, SD110, IXUS V2/300/400/430/500, IXY Digital 200a/300a/400/450/500

This sounds like it might be a defective CCD imager. If so, Canon should fix this for you for free, including free shipping both ways. This is regardless of your camera's warranty status. Please check the following two links for more info:

http://camerarepair.blogspot.com/2007/11/canon-digital-cameras-showing-black.html

http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=225&modelid=13390&keycode=2112&id=29819

Applicable cameras include:
A40, A60, A70, A75, A80, A85, A95, A300, A310, S1 IS, S60, S200, S230, S330, S400, S410, S500, SD100, SD110, IXUS V2/300/400/430/500, IXY Digital 200a/300a/400/450/500

This sounds like it might be a defective CCD imager. If so, Canon should fix this for you for free, including free shipping both ways. This is regardless of your camera's warranty status. Please check the following two links for more info:

http://camerarepair.blogspot.com/2007/11/canon-digital-cameras-showing-black.html

http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=225&modelid=13390&keycode=2112&id=29819

Applicable cameras include:
A40, A60, A70, A75, A80, A85, A95, A300, A310, S1 IS, S60, S200, S230, S330, S400, S410, S500, SD100, SD110, IXUS V2/300/400/430/500, IXY Digital 200a/300a/400/450/500

This sounds like it might be a defective CCD imager. If so, Canon should fix this for you for free, including free shipping both ways. This is regardless of your camera's warranty status. Please check the following two links for more info:

http://camerarepair.blogspot.com/2007/11/canon-digital-cameras-showing-black.html

http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=225&modelid=13390&keycode=2112&id=29819

Applicable cameras include:
A40, A60, A70, A75, A80, A85, A95, A300, A310, S1 IS, S60, S200, S230, S330, S400, S410, S500, SD100, SD110, IXUS V2/300/400/430/500, IXY Digital 200a/300a/400/450/500

This definitely sounds like a defective CCD imager. If so, Canon should fix this for you for free, including free shipping both ways. This is regardless of your camera's warranty status. Please check the following two links for more info:

http://camerarepair.blogspot.com/2007/11/canon-digital-cameras-showing-black.html
http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=225&modelid=13390&keycode=2112&id=29819
Applicable cameras include:
A40, A60, A70, A75, A80, A85, A95, A300, A310, S1 IS, S60, S200, S230, S330, S400, S410, S500, SD100, SD110, IXUS V2/300/400/430/500, IXY Digital 200a/300a/400/450/500