Sometimes your computer may be too slow and not working. I also faced this problem. It's not a special problem. It's a addition of some problems. So I will tell you how to keep computer fresh and save computer from becoming slow and hanging.
1. Keep Free Space
Don't fill the whole hard disk space. Because it's the main factor for hanging computer. So if you have filled your disk space, delete unnecessary files and programs and keep some free space in hard drive. Otherwise your computer will become slow that you would be not able to get speed of PC again.
2. Keep Computer Cool
Your computer may be turn off or slow if you use computer for a long time. So when your PC become hot, try to cool it from open place where air is available. You should not use computer while it is very hot. Turn off the computer till it becomes cool. You can use extra fan if it is need. Because sometimes laptop becomes hot for extra using. So take care of your PC.
3. Don't start many programs at a time
Starting many programs at a time may harm your PC. If you start many programs at a time, close some of them. Because it damages your hard disk and RAM. When I started many tabs from browser, my RAM usage has upgraded into 99-100% and my computer turned off automatically. So be careful about this.
4. Delete Temporary File
When you browse internet, your internet browser save some files automatically. So try to remove this saved files and clear cookies. Because it damages your PC speed. Moreover, your windows has some temporary file. You should delete them also.
5. Solve Memory Problem
If your PC is older model, you can not use PC comfortably. So try to add new RAM if there is any scope. Like that, if you have 2GB Memory, you can add more 2GB Memory. It will speed up your computer and give you a good solution. You can also add graphics card if you want to get rid of display solution. Because only speeding up your pc may not satisfy you. It will help you to run your pc quickly and will give you the best enjoyment for playing game, video editing, software making etc.