how to download modelsim software

you may get the installer in https://www.intel.com/content/www/us/en/programmable/downloads/download-center.html

However, windows 7 is too old. You will have to upgrade to windows 10 to use the latest release of modelsim.

https://www.intel.com/content/www/us/en/programmable/support/support-resources/download/os-support.html