I suspect some hardware problem the PC .so while performing post test the problematic area cause the lengthy boot.
so i did the following procedure to pin point the problem
- switch off the PC
- removed hard disk ,CD ROM and floppy connectors
- remved all internal USB and front audio connection
- switch on the Mother board ,
- still problem is there
- Replace BIOS Battery found it is 2.7 v instead of 3 volt but it is not the culprit.
- Clean RAM and and check CPU FAN ,even apply enough heat sink compound to the processor.
- Remove dust in the mother board with compressed air
- Inspect any visible burnt or damaged component in motherboard .
- check capacitor in the motherboard.
- power on the PC still the problem is there.wait more than 3 minutes to load windows completely.
- Normally during the boot some numbers and letters running in bottom right edge of splash screen which give hints about post codes.But in this case no such numbers appear.
- after windows loads I check the device manager and found 4 unknown devices in the USB area.and not any USB device detected in any USB port.
- I suspect USB controller causing the boot delay
- restart computer pressing f2 and enter the bios disable USB in bios,save exit
- Now the computer restart and boot without any delay
- add a 5 port pci USB add on card in the PCI slot and tell the customer to use that USB port,here after,
- This by pass surgery save a motherboard now the system is ok