i have installed magento in XAMPP in my win7 . when i tried to open localhost/magento/ the following error messege appeared
Fatal error: Allowed memory size of 792723456 bytes exhausted (tried to allocate 1764582776 bytes) in C:\xampp\htdocs\magento\vendor\magento\framework\ObjectManager\Relations\Runtime.phpon line 38
That means you php limit configuration isn't enough to run Magento.
Can you create a php file with phpinfo() and check your memory limits?