I have found recently that Panasonic TV's are a bit picky about display settings. My guess is that it's a setting on the TV, not the computer. I don't know TV's as well as I know computers, but you should try checking the advanced input menu.
Desktop 1: Windows Vista Ultimate 64-bit/Windows 7 Ultimate 32-bit | 8 GB Mushkin XP PC2-8500 | Antec 650 Trio | Seagate T3500320SV x2 | ASUS M3A78-T | Phenom II X4 920 | Samsung 22x | Antec 900
Desktop 2: Windows Home Server | Western Digital 500 GB x2 | Hitachi 1 TB Backup Drive | AMD Athlon XP 3200+ (still runs like a charm) | 2 GB PC-3200
Laptop: Windows Vista Ultimate 64-bit | Core 2 Duo P8400 | 9800 M GTS | 320 GB 7200 RPM HDD | 17" WXGA | 4 GB DDR3