I have a poorly g4 that has been discard for nearly 7 years! However, I been able to get it to boot by pressing down on the case but when it's running it's very unstable and the power mode keeps switching between battery (which holds no charge) and mains. When the mains is consistent I can get 5 mins out of the machine but as soon as it fails the laptop dies. Clearly there is an issues with the power board but what is the solution? I just need it to stay alive long enough for me to export all the HDD data. Any ideas?