Apple 20" iMac Desktop "colors crazy" Questions

the screan has lines going down it, and the color just completely like.. exploded yesterday now its all fuzzy and shaking and u cant read anything, i can makeout the shapes but its crazy kindly check ...

my g4 emac is acting crazy. it keeps freezing on me. when i open itunes it crashes on me. it is just not behaving properly. twice while writing this message my mouse arrow has froze and turned into ...