Hmmm the Dell inspiron 5150, one legendary laptop with umpteen issues, a laptop designed to break.
A promising contender for the stupidest laptop dell has ever built contest. However if my laptop survives this summer it may see its fifth birthday in november.

Follow at your own risk

When you press the power button, If your laptop powers on, the lcd panel is pitch black blank screen, not even back light power, no dell startup screen, you hear the fan spin up, you hear the hard disk spin up, in this state one of the 3 LED lights blinks for 7 seconds (I think numeric keypad), and then if everything switches off silent. The only LED on after that would perhaps be the battery charging indicator. it could be a memory DIMM gone bad, If you have two dimms try one, then the other to confirm.

If you can charge your battery elsewhere and power up your laptop
it means
a) AC/DC jack on motherboard has gotten loose, use solder to fix in place, shaking the adapter sometimes shows the loose connections.
Connector related problems, The USB and the DC jack connectors frequently loosen from motherboard. solder breaks. Do not move the laptop around too much. particularly with wires sticking in from the back. the tug of the cables cause them to loosen.
b) The Schmidt trigger chip near the DC jack has come loose.
Sometimes applying torsional force on laptop and pressing the laptop it near the power button makes contact temporarily, and laptop can get power, the mild bending of the motherboard aids contact, be careful .
c) your DC adapter has frayed, get a new one, confirm with someone else's adapter.

Overheating related power downs, laptop power down when hot and within seconds/minutes of booting.
Open the laptop and clean the fan and its related wind outlets.
This needs to be done once every six months (at least).

Dear reader, If you are reading this please share your other hardware related diagnostic and trouble shooting experiences with this legendary laptop. It is useful if the last remaining dell inspiron 5150 to have a handy troubleshooting guide. like how would I know if my graphics card or processor goes out next.

also see
http://support.dell.com/...
Tell-me-how service manual, owners manual

Hi kathryn,

Try re-posting with latitude d610 in the subject/message title, that way another latitude d610 user with more insight may respond.

You said "blue light on lcd screen near the power button" do you mean, "blue L.E.D." if so that might be a blue tooth/wireless indicator. otherwise I'm still trying to guess what you mean. you could be referring to the back light, or maybe the screen is on and a small portion of it has been colored blue.

The LCD screen is a matrix of red,green and blue dots(pixel). When the LCD screen is powered, there is a faint glow on screen due to the back light. The liquid crystal at each pixel can change its opacity in response to electric current. The graphics subsystem of the computer then controls the elctric current at each pixel to produce the impression of a display. In the reference to pitch black blank screen, I refer to a state in which the LCD screen is not even be powered on (no back light). This is in contrast to a state in which the LCD is powered on, and every pixel on the screen is set to block(turned off, in this case you can still see a faint glow in the dark).

Most cdrom/dvd and hard-drives drives just spin up on power on. the subtle question you need to answer is "is the machine booting" do you feel its trying to do more than just spin up , is it actually reading something off the drive. if that's the case then the graphics card/CPU/memory card(for the most part)/motherboard are all right. For this you need to actually listen and watch the dvd/disk activity lights keenly.

The key question is do you perceive your laptop to be booting but not showing anything on the screen, or do you think its hung. If its the former, you see hard disk activity and its just an LCD panel /connector issue. If its the latter it could be just about any serious problem, the smallest being the memory card and hard disk.

a small inexpensive tryout list :
* Maybe the LCD panel connector has come lose
* As in the above response it could be a bad memory dimm, try removing one or he other memory slot
* Maybe some component internally has just loosened and the bios refuses to boot minus this crucial component. (some bios refuse to boot if no keyboard is present.) so check whether keyboard connector is sitting tight.

also see
http://www.laptoprepair101.com/...

hth
good luck
-GK