5 GPU's at 1000w? Probably need more power.
Check your RAM? 4gb min and add virtual ram to include 16gb or your hard rive too.
1000W is plenty for 5 GPUs Eth only. with undervolt, 6 GPUs takes ~730W at the wall, so perhaps ~670W of PSU output. You could feasibly run 7 if there were enough connectors.
Dual mining different story, 1200-1300W PSU would be recommended.