There appears a vertical white bar on the center of my TV screen. The TV is out of warranty and a month and a year old. What could be the problem?

You may have to try reseating the ribbon cables between the LCD panel and the T-CON board, very delicate works!
Please download or read about troubleshooting T-CON/LCD panel failure mode to see if that is the symptom you are seeing.

http://www.scribd.com/doc/25276757/E40951307-TCON-Troubleshooting-10-22-09-OPT

PDF download: http://www.mediafire.com/?zzjygannjty

LCD panel: http://s807.photobucket.com/albums/yy352/budm/LCD%20panel/

If you are going to DIY and have proper tools, electronics knowledge, and know safety precaution then please read on:

Basic LCD monitor and TV troubleshooting guide:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
http://www.fixya.com/support/r7406380-tv_training_manuals
Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm
Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague
Parts: www.shopjimmy.com
Parts: http://interliquidparts.com/

Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx he can make you a set of caps.
Or www.digikey.com, just make sure to use caps with low ESR, 105c, high ripple current and long life rating such as PANASONIC FM or FC series.