You can't start it in any of the Safe Modes? Are you absolutely sure of that? Because if you can then you could initiate System Restore depending on the operating system to before all this happened.
It sounds to me that something was about to fail and installing the software triggered it.
What operating system and service pack is this, also is it 32 or 64-bit? How much memory (RAM) and free HDD (hard drive) space was there?
Do you have a System Recovery disk? If so it may offer you a boot method that can restore the computer to an earlier time.
Here's a Microsoft article on this stop error: http://support.microsoft.com/default.aspx?scid=kb;en-us;156669
Another option after clicking F8 to get to the Safe Mode menu would be to choose "Last Known Good Configuration".