try mrdemons first. i forget HP has built in software for diagnostic. if that doesnt work, click on start menu, click control panel, scroll to the programs and features, in it look for your graphics driver, right click it, then click uninstall, screen will flash to default, after uninstall, you should be prompted to reboot. for support website seach you computer model and it will list HP support site.
or you can search your graphics card by its model number and use link for AMDs website and download the auto detect hardware finder, and it will take you to the newest driver download. save the download and close browser.