Have you recently installed a new PATA hard drive?
If so, particularly if your hard drive is a WD drive, please check the jumper settings on the new hard drive.
WD drives often have specific requirements if the drive is alone on the cable. In this case, "master" may not be appropriate for the drive that is "alone" on the cable. Either refer to the "alone" markings for jumper positioning on the top of the drive, or refer to the settings in this WD link:
»wdc.custhelp.com/cgi-bin/wdc.cfg ··· **&p_li=
Please note that a system that has many drives configured into numreous raid arrays may take longer to post or boot than an average system. This may be normal.
Some motherboards may offer you the ability to disable unused raid controllers in the bios which may also speed things up.