Reddish vertical lines on LCD & view finder

hate to say this but it sound like you need another screen replaced

Even it is old model, it still has very good lens. It depends what do you want use it for. Good lens (in compact cameras, or for DSLR) are still expensive, and will be...

Please take a look at the symptoms listed here, and see if it's what you're experiencing.

http://esupport.sony.com/US/perl/news-item.pl?mdl=DSCF717&news_id=161

Sony had a certain issue with the CCD chip on this camera. If it's this issue, they'll fix it free plus $20 until March 2010.

Due to ccd imager chip failure in DC-F717 camera, you do not get live view to take pictures in LCD and view finder. CCD imager chip will be replaced to correct that problem, Sony offers free of cost repair for same problem in this model. Click Sony CCD Imager Support for details.
Thanks.

Sony DSC F717s manufactured from 2002 to 2004 had a CCD chip with an epoxy base that gave off a gas vapor if overheated (eg in a hot car in summer). Sony was replacing these faulty CCDs with a new one on a ceramic base, however, this free repair program has been discontinued by Sony.

http://www.imaging-resource.com/badccds.html

The above link will take you to a web page by Imaging Resources explaining the problem they found. It has some photos of an LCD displaying a view from an affected camera. This is no solution for you, rather a diagnosis. There is a YouTube video showing someone replacing one of these faulty CCDs. It's less than 10 minutes, real time.

http://www.youtube.com/watch?v=rnZdEc9KY-U

CCD is DEAD

Sony is fixing this through Sept. 2008!

http://esupport.sony.com/perl/news-item.pl?news_id=161&mdl=DSCF717

This sounds like it might be a defective CCD imager. If so, Sony 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 link for more info:

http://camerarepair.blogspot.com/2007/11/sony-konica-minolta-cameras.html

Applicable cameras include:
Cyber-shot DSC-F717, F88, P10, M1, P12, P2, P31, P32, P51, P52, P7, P71, P72, P8, P92, T1, T11, T3, T33, U10, U20, U30, U40, U50, U60, V1

CD Mavica MVC-CD250, CD400, CD500, and FD Mavica MVC-FD100, FD200

Digital Camera and Video Phone Number 1 800 222 7669 - it's automated, just say your model number, then "no" to accessories, then "no" to connection problems, then "picture" for ccd issues. Its that easy!

Yep, sounds like a bad connection on the display's internal cable. Need to check and see if the Electronic View Finder also shows the lines. If it does, then it may be a sensor problem, instead. If not, then the display has a bad connection or has gone bad itself. In either case, it's not a trivial issue.