iMBP 13" (2009 revision) display a prohibition sign upon bootup

[TonyNZ09AUK]

Hello,

I'm new to this OS, which is a iMBP 13" (2009 revision). I'm experiencing abnormal bootup. The bootup screen display a prohibition sign upon bootup after installing Security Update 2010-001 for Snow Leopard. There is no error message I can write down nor excessive fan noise coming out from the laptop.

Thanks for your help

Tony from New Zealand

Computer Spec: 13-inch: 2.26GHz
13-inch: 2.53GHz
W/ v10.6.2
Intel Core 2 Duo
2GB Memory
500GB hard drive
SD card slot
NVIDIA GeForce 9400M graphics
(2009 revision)

 

[Kim Philby]

Can you post a picture of the screen?

 

[TonyNZ09AUK]

On boot, it display an image like this:

 

[JediMeister]

What to try. I am reasonably confident that the archive and install will fix the issue without needing to go the more excessive route of the erase & install.