Red vertical lines and lock up of pc

hello everybody

ok here is my problem. i have a old desktop i use all the time but lately i get red vertical lines on monitor and my desktop completely locks up and i cant restart, i have to wait a bit then i can restart it and within minutes it happens again. i noticed i was keep getting port attacks from attept hacking but my firewall detected and stopped it. now i wonder if that has anythign to do with it or if my video card onboard just gone bad.

any ideas?

many thanks

p.s am using my laptop to post here lol