Get Microsoft Visual C++ Express here or CodeBlocks here.
Get STLFilt here to radically improve error messages when using the STL.
Get these two can't live without C++ libraries, BOOST here and Loki here.
Check your code with the Comeau Compiler and FlexeLint for standards compliance and some subtle errors.
Always use [code] code tags [/code] to make code legible and preserve indentation.
Do not ask for help writing destructive software such as viruses, gamehacks, keyloggers and the suchlike.
Might want to look into Viola-Jones image detection or Google around for Haar-like feature detection. You might also look at the OpenCV library (link); I've used it before and it's a solid library.
You will probably have to address orientation in a somewhat more complex way. I am not an expert on this subject, but I was taken to understand that many computer vision methods are very sensitive to differences in orientation. This may be a subject of ongoing research, so you might check out Google scholar for some idea.
Hope that helps point you in the right direction. Let us know if that was helpful and what you end up doing!
All advice is offered in good faith only. You are ultimately responsible for effects of your programs and the integrity of the machines they run on.