Ok for this world it says you have to destroy a computer surrounded by 8 stone pillars. I have killed all the enemies and found a place with 8 stone pillars. However it doesn't look like a computer(just a stone something) and grenades don't blow it up. Also I cannot attack it with melee weapons. Am I missing something or do I need something stronger then krak grenades to blow it up? Thanks.

Its been a while... But I recall that these types of things required you to move a marine next to it and hit the "use" button. Similar to the campaign mission with the techmarine using his claw on the computer station.

Ok I had given up but if I didn't save over that game I will go back and try that.

Editing to add: Ok I tried it and it didn't work. I will just write off this target as broken, go back to an earlier save and skip it. Thanks for trying.