Did you purchase the BIOS separately? Did you buy from Dell or from a third party (who may have replaced the BIOS with a BIOS tailored to a different board)? If purchased new from Dell or one of their distributors, then you have a warranty period (what is warranted and for how long is specified in the paperwork accompanying the board) during which you can receive tech support from Dell free-of-charge. Have you tried this avenue? What have they told you?

Dear Sir,

I am user of GX620 & i have purchased refurbished mother board of dell GX745 and facing problem of said error. please advice

Refurbished? What does one do to a mother board to refurbish it I wonder?

Back to your problem....

Gaze at every square millimeter of the board and look for jumpers and pins without jumpers. There maybe something printed onto the board around these..could give you a clue.

Have you checked all the cabling and every connector yet?

Dear Sir Jpool,

You are absolutely right I have replaced I/O board & resolve my problem.

Thanks