Is there any chance the drive is bad? I would test it using WD Diagnostics or SeaTools depending on the brand first (you can download them for free at Western Digital or Seagate support sites.
Once the drive is checked and okay (which I will assume is the case now), do a fresh clean install of Windows 7. As a first step choose custom install and then delete all existing partitions, then install to the single remaining unpartitioned space.
After the Windows 7 install is done (and if you are using a USB stick insure that you use it on a USB2 port!), then install the drivers for the chipset and devices that you can download from the laptop manufacturer support web site by selecting the correct laptop and OS details.