One item of note for notebook (or net-book) owners is to ensure that the RTC battery is fully charged before use.
Most pro-grade models have rechargeable RTC batteries, some have disposable RTC batteries. The disposable RTC batteries (usually a Lithium coin-cell CR-prefix, except Dell) must be replaced if voltage falls below 2.85V @ 20°C. Some OEM's use a Lithium coin-cell with leads. In this instance, i salvage a small coin-cell socket from a dead motherboard & wire the old-cell's leads to it & then find an electrically-insulated (non-thermal-zone - 40°C max) place to mount it with a common hot glue-gun. I check with a handheld WiFi detector that runs on Lithium coin cells (if it can't light up the cell is a dud). This shows that each cell can handle a standard load. Rechargeable RTC batteries (ML-prefix) usually require 16-24 hours to fully recharge from a discharged state.
I have personally seen a dead RTC battery cause a black-screen issue on at least one notebook. Usually a bad RTC battery will simply cause the time to be reset, yet other affects may occult your best efforts.
If your main battery has little capacity even after a full charge, discharge it using Memtest86 (or similar), charge it to full, then repeat 2 more times. Ensure that it is stored between 5°C & 40°C (preferably 20°C) as these battery-type's lifetimes are reduced at 'extreme' temperatures. Never attempt to charge a battery that is outside that temperature range!
