Computer always crashes /shuts down when playing videos online

I have a homemade athlon amd with nvdia gforce C61 [GeForce 6150SE nForce 430]
and phoenix biostar 1.06 bios, with ubuntu OS. Could this be because the bios hasn’t been updated? or the nForce drivers? also can someone paste the correct link to update both the drivers and bios for my system? do i need a flashdrive for the biosstar update? i went to the biostar website but can’t seem to get this solved. Must be a noob at this. apologize

also is this the correct driver which i’m downloading for the nForce 430 C61?

also should i leave the bios settings as the normal ones if the clock rate processor is 66 mhz? or is this something i should manually change along with the Voltz settings? i notice my computer makes wierd noises when playing videos when i manually change these

I just cleaned it out, had a TON of dust under the CPU fan and clogged in that metal wire cage thing too. Maybe that was causing the CPU temp to always be around 80 C? i’m reading it should be way below that always?