computer troubles

my computer is pretty old.
and like i said in one of my previous posts, im not very knowledeable with technology.

anyway, my computer screen does this weird flickering thing then will go black, usually if it stays black i can just turn off the moniter, wait a bit and turn it back on. but some times it this even weirder thing where it turns BROWN, of all colors! (i dont like brown) and no amount of turning off the moniter will help, as soon as you turn it off you wont ever get it to turn back on. so i turn off the tower and leave it alone for a couple of days.

well this time when it did this, and i turned it back on, it turned brown before my desktop was even done downloading! and its been doing that for about a week now.

i know i dont have much virtual memory left but ive been cleaning out my computer and deleting tons of stuff.

recently i deleted over 17 thousand pictures of random stuff i dont even remember seeing nor did i want to keep, im down to below 15 hundred
and ive been deleting music files as soon as im done downloading them(after i put them on my mp3) so i just have to go through a ton of word docs and amv's(anime music videos) and delete them (im going to delet alllllll of the amv's, all 203 of them)

so i dont know whats wrong with it any more, we recently werent able to turn it on at all cuz of the ice storm, so we called geek squad to come fix it
they swindled us, we asked them to tell us if it would cost as much as a new computer and if so we would just get a new one, they never told us till it was too late *shakes fists at geek squad*

any ideas to figure this out?