iMac blue screen of death

[FerraraZ]

I recently bought my mom an old imac g4 from amazon. Its her first computer and she's computer illiterate so the imac was attractive and easy. Whats odd is it seems that everytime she is on youtube for an extended period of time the computer locks up and black lines of text show with all kinds of errors. I have no idea where to trouble shoot because I've had macs before and never had one crash with a hardware failure. So far it seems to happen randomly but will happen atleast twice a day!! Any idea or solutions? I'll post specs shortly.

Product here:

http://www.amazon.com/gp/product/B000PQJS9I

One thing I dont see listed is the vid card which I believe is a GeForce 2 MX 32mb

 

[Dahak]

from what it is sounding like is whats called a kernel panic, which could come down to 1 of 3 items,
1) bad os install ( not very often or likely unless messing around)
2) bad ram
3) bad logic board(motherboard)
with these ones especially i have had and seen where if you are upgrading the internal memory and the internal thermal compound is cleaned off and reapplied properly it damages the cpu and you have to replace the logic board

for diagnostic software, there is the apple hardware tests which is usually on the install cd for os x, you hold down the D key or may be a separate cd
techtool pro, which is a payed program, or tech tool deluxe, which you get with apple care.
or if you have another mac that is a g5 or g4 you can boot up the other mac with the T key held down which turns it into a large external hard drive and if you plug a firewire cable between the 2 and on her g4 hold down the option key or in the startup preferences pane you will see the external hdd and you can start up off that to see if the issues still happen. if they do then it is hardware.