Hello Mohamed,
How you doing.
In trying to over-clock that CPU I think your system is being pushed too hard because of the motherboard's inability to support a 133MHz FSB. It's early BX chipset only does 66MHz or 100MHz and altering it could do some serious damage. Anything over 100MHz isn't officially supported or even recognised.
the board will run 800MHz CPU's when using a 100MHz FSB and the latest BIOS, but that's the limit. Better chipsets like the Intel 815e can run the FSB at 133MHz or higher.
You'll need to get a new CPU or you could get a brand new device that allows the latest Intel CPU's to run on older systems:
http://www.tomshardware.com/cpu/02q3/020924/index.html
I'd weigh up the cocts of upgrading as opposed to using a cheap AMD solution.
I downloaded the manual for your SE440BX-2 and tried to find any extra FSB settings. I've also looked at the specification changes/updates but I'm afraid there aren't any - the only option is to alter JBA1 and enter the configuration menu. Even then, all that will do is allow you to change the CPU type and not the multiplier or FSB.
You also informed me that you're using CPUCool to alter the FSB through Windows, and the options were 103 or 124MHz. If you were able to alter the FSB manually to 103MHz using CPUCool, be very careful and stay at this speed if the system's stable. Such programs can play havoc.
Physically, when the FSB is at 66MHz, the AGP will run at the same speed and the PCI will run at 1/2 this to give 33MHz. When you alter the FSB to 100MHz, the chipset will alter the FSB clock/divider ratio accordingly to still keep the AGP and PCI speeds in check: It will run the AGP speed at 2/3 of the FSB speed and and the PCI to 1/3 so that they can be run at the correct speeds as before: 66MHz and 33MHz which are the official standards. The clock divider cannot be altered physically or programmed through software.
Some later BX boards from other manufacturers like Gigabyte unofficially offered a 133MHz FSB support and at the same time allowed you to alter the alter the clock divider and keep those AGP, PCI devices safe. This board doesn't - it will still use the 2/3 and 1/3 divider even if you can go higher than a 100MHz FSB through some third-party software like CPUCool. This is where the *serious* damage can occur.
When you changed the FSB to 103MHz with CPUCool, you were running the AGP at 68MHz and the PCI 34MHz. This is OK and shouldn't give any problems with the CPU (PIII 550MHz which now runs at 566MHz), the AGP or PCI. I would take this as the best option with this board, despite the CPU's ability to go higher.
But when you ran the FSB at 124MHz, several problems occur because of your board's fixed FSB/PCI clock-divider:
.The CPU is running at 682MHz without extra cooling or extra core voltage.
.The AGP is now running at 81.74MHz . The PCI bus (and IDE channels) nows runs at 41MHz. Ouch!
You could do some serious damage to your peripherals at this speed. If they run alright at 103MHz, stick with that and they should be OK, but 124MHz is not worth the risk.
Some Useful Intel Links:
Information index on the Intel SE440BX-2 motherboards given by WCPUID: http://support.intel.com/support/motherboards/desktop/SE440BX2/
CPU's Supported by this board: http://support.intel.com/support/motherboards/desktop/SE440BX2/procsupp.htm