Follow these steps to fix a Blue Screen in Safe Mode
* Once booting start, select "Safe Mode" from the boot menu.
* Scan your hard drive by running your antivirus software. If the program locates an infection, move it to your vault or follow the on-screen instructions. After program completation, if a virus was removed, attempt to reboot your computer and see if this clears up the problem. If not, restart your computer in safe mode.
* Restore your computer to a previous point. Click on the "Start" button. Select "All Programs", "Accessories", "System Tools" and finally "System Restore". Choose a restore point on or before the last day your computer worked without error. Finally Reboot your computer to see if it loads correctly.
I guess this is comman when you are installing windows 7 for firstime on any PC, the best suggestion please wait patiently untill it returns because this where your system is being configured.