Thin bar in the middle of the screen showing the picture

Most likely the vertical oscillator circuit has failed. As CRT televisions have gone the way of the dinosaur, my advice to you is to give a fond adieu and invest in a new TV.

If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/
Line, faults & possible causes to LCD screen are given with illustrations. You can get an idea about the fault to an extent.

Vertical scan output section circuit should be checked. Contact any service technician.

if the line is pixel thin, it could be a bad lcd panel. if it is a wider bar, it may be in the video circuitry. many of these sony tvs had bad panels, and sony has extended the warranty. call up sony with your model and serial # and date of purchase and try to get them to help you out, that is your best course of action. let me know if you need more troubleshooting assitance.

It has a bad upper Y driver board.

The problem is in the vertical section of the main board. Bad capacitors and maybe the vertical IC. If you are not inclined to be a tech you will have to take it to a shop.. I don't know what they may charge but I normally get $69- $89

If you go to 1800customersupport.com it has some good info. Alco Electronics is the maker.

is that a flat screen LCD ?

Can you describe in a little more detail what the symptoms are? Are the streaks thin lines or are they large thick swashes of Blue? Is yur video still visible? Sounds like it may be the blue convergence amps or the resistor tied into the amps. is there anyway you can post a picture of your screen distortion?

Thin white dashes on top of screen is PERFECTLY NORMAL. It is nothing wrong with the TV, it is the broadcast. What you are seeing is the very bottom of the timecode running. It doesn't happen all of the time or all channels. It usually happens with old 4:3 commercials predating "Digital TV." This is mentioned in your Users Manual. You should be able to adjust the horizontal/vertical position in the menu settings.