Television and Home Theater

Hi im a newby 2 this forum,but from some of the posts i read here i see there is sum really clever people [unlike myself] lol.The problem i have is a DMTECH [i know BIG mistake] any how its the 26inch dvd combo,i only use this as my pc monitor.i have a nvidia gforce 7300 gs graphics card,i have it connected with the vga{D-Sub it says in book if there is a difference} when i change the screen resoloution to anything above 800x600 i get vertical lines on my screen+whats quite alarming is that the colours are so vivid,not like any colours that you would think a graphics card could make,this ev

I have this Sharp TV (box not LCD) and all of sudden yeaterday the screen just went a funny colour its like a green circle in the centre and then red in corners? any suggestions ? think the model is 28LF928 

Please somebody help me?I have a 30 something inch rca true flat that I got from my buddy. In the back it has your standard red yellow white jacks but it also has green blue and red jacks. When I connect the right colors to these jacks form my xbox 360 it sais unusable singnal. Does my tv support HDTV???

Please help.