Wipe the HD to clean it of any remaining infection: SSD / HDD : Optimize for Windows Reinstallation
Check that you have the latest BIOS version update from the mobo maker's SUpport DOwnloads webpage for your model.
Clear the CMOS: Clear CMOS - 3 Ways to Clear the CMOS - Reset BIOS
Check the SATA controller setting. Try AHCI first, then IDE if necessary.
Where did you get Win7? Did you burn it yourself. Verify burn with ImgBurn by loading ISO and DVD. Burn again if necessary using ImgBurn at 4x speed with Verify.
Try installing from USB flash stick: USB Windows 7 Installation Key Drive - Create http://dottech.org/featured/9157
Windows 7 USB/DVD Download Tool