If you can boot, can you connect to the internet? If so run Windows Update after enabling Automatically get recommended drivers and updates for your hardware
install all Important and Optional Updates which should include missing or outdated drivers.
Then look in Device Manager to see what is missing, import them from the Support Downloads webpage for your model PC or Device. We can also help you find them if you'll post back the device make/model. As requested please also fill in your System Specs in bottom left corner of post.
If you'd rather start over then read over these steps for Clean Reinstall - Factory OEM Windows 7
which are the same for retail. Note especially how drivers are best handled.