We have this model of laptop in our office. We have tested the memory, hard drive, motherboard, cpu and video. All tests have passed. We also switched out the ram with a known good stick, kept the battery out and updated the bios and ran a few burnin tests. All drivers are good as well. This laptop still doesn't always boot up. If it does boot up there are times when it just shuts off. Does anyone have a solution to fix this.