DELL Dimension 9100 desktop (PSU)

look here
DELL Dimension 9100 No Booting diagnostic light 1 green 2 3 4 green

Also bear this page and links in mnd

Does sound like your motherboard defo, It could be that the power button is not wired correctly to the board, but that is prob no the case if you have not taken any of the wires out, or messed with the inside before the problem happened.

You can get a replacement board, try going on to ebuyer.com, ( http://www.ebuyer.com/store/Components and select motherboards on the left) they do a wide selction and at good prices. Chances are you can get the same board, or one simiar just by entering the make of the board (have a look on the board, for somthing like asus, gigabyte, asrock etc) and also for the type of proceser you have (i.e an AMD or a Intel)

if its unmodified, then its probally an Intel board with a "T-Socket" slot otherwise known as a 775

get one of these and u can keep your processor, RAM etc..

that of course, if it is your motherboard!! If you've replaced the PSU thats your best bet.

i wouldnt do it your self unless you are confident in doing so

Hi
With that scenario i would recommend you check the front panel assembly where the power button is located and also have you tried to reset the CMOS from the motherboard.

The power light flickering is normal. Most pc power lights flicker to show it is operating. Also your light on you cd rom or dvd rom will flicker when you put a disk in it. Try it now - put a disk into your cd rom [ or dvd rom if you have that] and watch the power light flicker.

Here ya go
http://support.dell.com/support/edocs/systems/dim9100/en/SM/parts.htm#wp1077838

try a new cable for the hard drive and disk drive and see if no result try diferent hard drive please thanks

Not without major case modifications. Dell uses Dell specific rather than industry standard motherboards on all their systems except the newest XPS line. Sorry.

There are three components to the Dimension 9100 power system. The power supply, the motherboad and the I/O adapter board.

You can get an I/O Panel here:

http://cgi.ebay.com/DELL-F8913-DIMENSION-9100-FRONT-I-O-PANEL_W0QQitemZ200247697428QQcmdZViewItem?_trksid=p3286.m20.l1116

Motherboard here:

http://cgi.ebay.com/DELL-XPS-400-MOTHERBOARD-cn-0fj030_W0QQitemZ290257206473QQcmdZViewItem?hash=item290257206473&_trksid=p3286.c0.m234

plz check the ram and powersupply unit and try to reset the bios

there are fuses inside psu`s some are solderd and some pop out it i would suggest that u throw the psu away and buy new chances are that it will only cause continues and may even result in 
complete mobo failure problems heres a link to a cheap psu   http://www.microdirect.co.uk/(3649)400W-P4AMD-quiet-PSU-with-PFC-20-pin-24-pin.aspx or a more upmarket more powerfull http://www.microdirect.co.uk/(11879)ThermalTake-TR2-500W-Black-Silent-ATX-12V.aspx the choice is yours.