It may well be that your battery has run down and is not recharging fully. The machine will close windows when it goes below about 8% of charge. I overcame this as follows.
With just battery power, no AC adapter connected, on boot up press the appropriate "F" key to open the blue set up page. Then just sit back and wait for the page to gradually fade. This takes a long time, can be a few hours. I left mine overnight! When the screen is totally blank then you know the battery is fully empty. Then connect up the ac adapter and without switching the machine on , let the battery fully charge. You should have different colored lights to tell you when it is charging and when it is fully charged.
In normal daily working if you frequently use the ac adapter as the power source, remove the battery. Double wammy here as not only do you preserve the battery but also keep your processor cooler as you get a bit of airflow in the battery compartment. If your laptop gets hot then stand it on an open wire cake tray (Remove and consume cakes first)