Photoshop Problem on launch

Question

I've Photoshop CS5.1, the problem is that when i launch Photoshop, it doesn't even appear the splash screen, it just appears:
"Adobe Photoshop had stopped working"
The details of the error are:
Problem Event Name:
APPCRASH
  Application Name:
Photoshop.exe
  Application Version:
12.1.0.0
  Application Timestamp:
4d90cf71
  Fault Module Name:
KERNELBASE.dll
  Fault Module Version:
6.1.7600.16850
  Fault Module Timestamp:
4e21132b
  Exception Code:
c06d007e
  Exception Offset:
00009673
  OS Version:
6.1.7600.2.0.0.256.48
  Locale ID:
1040
  Additional Information 1:
0a9e
  Additional Information 2:
0a9e372d3b4ad19135b953a78882e789
  Additional Information 3:
0a9e
  Additional Information 4:
0a9e372d3b4ad19135b953a78882e789
I have installed some Red Giant Software Plug-Ins recently, but when i deleted the folders, the error was still there!
Any solution?
Thanks!

Answer 1

There actually is an issue with switching my bad kernelbase.dll with the good one...
I downloaded a normal copy of KernelBase.dll, but i can't manage to delete the bad one, for then put the good copy in the right place!
I tried with this command:
del C:/Windows/System32/KernelBase.dll
And it didn't work
So i tried this one, with the command to force:
del /f  C:/Windows/System32/KernelBase.dll
And it didn't work either,
I tried to run Windows 7 in safe mode to actually access to it and run the CMD and put those commands in, but it just doesn't work!
The problem is that i deleted the Photoshop Setup file, so i don't really know how to fix this problem, and i don't either now if reinstalling is prossibly going to fix it.
Thank you for support.