Here is some help for you, those advice can help you fix your computer issues very quickly.
1.Click Computer on your desktable and right click Disk C to select Properties.
2.Click Disk Cleanup, you'll see a window just as right, this process need some minutes.
3.Under Disk Cleanup there are Files to delete, tick the files you don't need to free pc space, finally click OK.
1.Turn on your PC and press F2, then select CD or DVD, it will start loading its files, later you can see a window like below, you can select languge and click on Install now.
2.There will be a agreement license, select Agree. Select custoem(advanced) next create a new drive, click on drive and then click new, a new dirve can be created and you can see a window below.Choose any drive you want to install window. Click Format and Next to proceed.
3. When installing, don't plug in or off your device.After it installed, your pc are been rebooted and you can see a User Setting, just type your name and password. Then click on Next and a new window open.In this step you must activate your windows, add a Product Key and click OK.