Check your machine operating system configuration and search for jdk file.
For example, if your system is 32-bit, search for JDK download for 32-bit windows 7. You may get many sites to download application, here I have given installation process steps from download.cnet.com
Step 1: Download File
Step 2: After .exe file is downloaded, save the file.
Step 3: The file will be saved and installation process starts.
Step 4: Click Next
Step 5: The path will be set and click Next to install
Step 6: JDK is installing
Step 7: Click Next
Step 8: Program starts installing
Step 9: JDK is installed. Close the window