It could also be some overheating issues; clean the vents with airduster and make sure air vents are not blocked. Always set laptop on a flat surface, so air can flow freely around and underneath it. Games and other mass programs can drive CPU usage toward 100% and contribute to overheat.
Scan with a antivirus program & spyware/malware program to see if there is any unwanted programs. Remove the unnecessary programs and applications.
DEFRAG C: & CHKDSK C: ; use external harddrive for all future downloads.
Clean up registry problems using Reginout registry manager.
If problem persists, last resort is to reformat your laptop, hard disk clean and reinstall OS. But before doing that, try the steps above first.
Also, try remove the battery and charger/ac adapter/power cord from your Toshiba A205, press and hold the power button for 20 seconds to discharge any residual current inside the laptop. This clears your RAM and is like a hardware reset. Replace the battery and charger/ac adapter/power cord and turn your laptop on.
Check if it's something to do with your laptop power cord or power source problem. Insufficient power might cause some of those issues as well. Take the battery out and power on your laptop with the charger only. Make sure your laptop power jack and charger plug tip are securely connected. If power jack is loosing you can find laptop power jack on ebay. However, fixing and soldering the power jack requires professional skill.
Also the green/blue LED on charger need to be constantly on without blinking. If not, replace the defective charger. You may consider getting a charger from company like topmic.com. They are few of online stores i know who offer a charger under lifetime warranty. Since battery/ ac adapter won't last forever, lifetime coverage can certainly save your some money.
Wish the Best.