I recently replaced my power supply on a dell 9100 Deminsion. I purchased the 600w one and installed it a day ago. Upon installation, everyting seemed to boot up like normal... fans running hard drive spinning, and what not. (I am not technical at all and for that I am sorry). I had no signal to my monitor, so I replaced the video card yesterday, and I still have no Signal to monitor. The computer runs the same as it did before, fans kicking on and hard drives turning... but still no vid signal. I've tried a number of "heard it from this guy" things to do like powering down and unplugging the machine. Hold the power up button for 30 secs and then plug in and power up again. Nothing seems to work. My Vid card is an Asus ENGTS450, if that helps at all... Any suggestions? Could RAM be an issue? Thanks for anything and everything... really at the end of my rope with this tower. USBs wont work either (mouse and keyboard dont respond) but that is another problem for another day I think.

There should be 4 diagnostic LED's between the front panel audio sockets and the USB sockets. What do they do?

A 2 and a 4 are lit up on the front along with what I assume is the hard drive (cylinder lookin thingie). Cylinder goes away after a few seconds but 2 and 4 remain. really sorry bout the non technical terms...

I need to know what colour they are as they can be lit green or orange (altho Dell call it yellow).

According to Dell that's graphics card failure. You should remove the card, blow the slot out, and refit the card!

after that if it still has the same two numbers lit, can it be something else? Still no signal and same two lit after refit. Thank you for the help by the way.

It may be a fault on the motherboard. Have a careful look at all of the capacitors to see if any are domed and/or leaking. If you find any like that then replacing them should get your system working again. They can go open circuit which can cause 1 or more voltage inputs to not get to the graphics card. I have replaced capacitors on quite a few Dell boards myself with a %100 success rate. If you are not experienced with a soldering iron then you will need to find someone that is as it can require a fair ammount of heat to replace them as 1 leg is usually attached to the ground plain of the motherboard.

If you don't know what a capacitor looks like then google for a photo of one.

I do thank you for your help. I think I may have to take it in for someone to take care of the issue. I looked over the motherboard and didnt notice any of the capacitors bloated or leaking. All of them looked pretty nice. Little dust here and there, but not much else. Someone told me to check the RAM, but I think im going to stop and check with someone to take care of it. Thank you again!!

If you wish to check the ram then you can google and download memtest. The thing is tho, the diagnostic LED's point to graphics being the problem. A ram problem would show a different pattern!