Unable to boot Galaxy S - only see a picture of phone -> "triangle with an exclamation point" -> computer
Now, the only option you've left is to Flash your ROM. Flash any one of OFFICIAL firmware from below:  


Gingerbread 2.3.5 XFJVA   
Gingerbread 2.3.5 XXJVT


Follow the links &amp; do EXACTLY what it says. It'll take less that half an hour. Just, do it.. Nothing more! 

Don't do any experiment before you boot your device. Plus, don't follow any non-matured instructions from forums etc.