You appear to have memory issues; run the boot version of Memtest86+
paying close attention to Parts 2 and 3 of the tutorial.
Do you have any mismatched memory (memory bought at different times/from different manufacturers/at different frequencies)?
If memory passes, run Driver verifier:
1. Backup your system and user files
2. Create a system restore point
3. If you do not have a Windows 7 DVD, Create a system repair disc
4. Run Driver Verifier
If Windows cannot start in normal mode with driver verifier running, start in safe mode. If it cannot start in safe mode or normal mode, restore the system restore point using System Restore
OPTION TWO. Thanks to zigzag3143 for contributing to the above steps.