With HP you're fighting the worst load of corrupting preinstalled bloatware in the industry, which throttles Windows 7 from its native perfect state.
So you've got the right idea to reinstall, but likely have some corrupt code in the boot sector. So first read over these steps to get a perfect Clean Reinstall - Factory OEM Windows 7,
then boot the Windows 7 installer, at first screen press Shift + F10 to open a Command Box, run Diskpart Clean Command
to wipe the HD and boot sector, after it completes, close Command Box, click Install Now, create New and Format your partition(s) as desired to begin install to the first partition (after small boot partition created).
Be sure to stick with the step in the tutorial which explain how drivers
are handled in Windows 7, the tools and methods which will get and keep a perfect install.