screen black out

hi. this could be long bt pls hlp. i hav dis laptop Toshiba satellite l305. S5917. Bought at end of 2008. it has intel celeron procsr with 1 gb ram. it came with win vista bt i upgraded to w7. it ws working fine until one day when the screen blacked out when w7 was starting up. i had to restart thrice as it blackd out either at the boot or at the desktop screen. the same thing happnd everybtime i switchd on my laptp. i re installed the os but to ni use. i had to restart twice or thrice before it was stable. then i strtd it with xp and ubuntu , which i have installed in it. the same prob. i had doubts in the display and pluged my dsktp monitor to the laptp. the dsktp screen blackd out. (also the screen is not black all the time. it is orange sum time or blue sum other time, both in the dsktp monitor and lap display) . so no prob with disply. i noticed that the hdd access light in d laptp wd either glw without blinkin or not glow at all when it blcked out . so i removed d hdd frm d lap nd plugged it into my dsktp( a new one with i5). it worked jus fine. once when i switchd on, w7 loaded nd d hme screen was displayd. aftr 2 min or so it hpnd again nd the screen went orange fully. i removd d ram as such nd to my surprise nothing happnd. the screen was orange wthout any disturbnce. ( when i rmvd d ram when thw laptp was running normally der wer some dots on d screen nd it restartd). nd one more thing i recently noticd was that the color is nt random when it happens. screeb becme white when i was using notepad. it is fully black when it hangs during startup. it is orang whn ir hangs at home screen, as i hav a orange shaded canyon as my background. (the one in w7 united states theme. )
i hv my files backed up bt i want o know wat is wrong with this laptop. pls hlp guys... thanks.