I am having an ongoing issue with a Dell Optiplex 755. It randomly shuts down - usually it seems to be connected with an update and after a day or two seems to settle down. This machine has recently been reassigned to handle a program that should run 24/7. So, in the past it was OK to wait out the quirks but now it needs to be ready to go all the time. I have run the Dell diagnostics - no errrors. I consulted with Dell chat (machine is still under warranty) and they suggested I update the BIOS. Ran the Bios flash the chat-er sent me via a link and updated from BIOS A09 to A17 and now it just power cycles - it seems to want to start but never does. The power light is solid amber and the numbers 1, 3 and 4 show up for a few seconds and then all goes black - then the cycle repeats. I let my Dell chat-er know the status via email and I have not heard anything from him (have I been ditched??) I have been researching this on and off for a couple of years (like I said - it would resolve itself so I was never under the gun to get it completely fixed) and have tried a number of things in that time period but now what it is doing is extreme and I really need the machine going. From what I am reading I think it may be a power source issue...can anyone walk me through what I need to do to 1)verify that it is the power source and 2) what steps I need to take to replace the power source if indeed it needs to be replaced? I am leaving work for the evening so I will check back in about 16 hours. Thanks! P.S. I am running Windows XP 32 bit.