I have an XPS 435MT (more details below). Last night I shut down and after Windows closed I noticed a splash screen warning me that updates were now installing and not to manually turn anything off until the process was completed. I left it to do it's updating and went to bed.
Now this morning, I've got a brick. When I press the power button, it flashes orange. If I hold it in, it will blink orange every five seconds or so. The fan isn't operating and the CPU is completely quiet.
I unplugged it, waited, plugged it in again, same thing.
Is it possible that one of the updates (a Windows update, I presume) disabled things? I'm at a loss. Any trick I can employ to get it to boot up?
Studio XPS 435 MT, purch. 6/2009
Intel Core i7-920 processor (8MB L3 Cache 2.66 Ghz)
512MB ATI Radeon HD 4850 video
1TB Serial ATA hard drive (replaced with similar sized HDD Jan 2012 after crash)
6GB DDR3 SDRAM at 1067MHz
"Is it possible that one of the updates (a Windows update, I presume) disabled things?"
No. Windows cannot be responsible for a system not turning on. I would first try removing any external devices (sound, USB, etc.). If not, then try clearing the NVRAM/CMOS using the jumpers on the motherboard. If that doesn't work, then remove any unnecessary devices (drives, memory, graphics, etc. - if you remove all memory, you should get a beep acknowledging that there is no memory installed).
I went through the exact same scenario over the past two weeks. Power supply was functional and power button responded identically. Dell suggestesed replacing the motherboard (a first for me as motherboards seem to rarely just "die") which I did for $65 off EBay and computer operated normally again for one week until yesterday when the exact condition returned. After disconnecting all hardware from the motherboard (hard drive, cd-rom, EVERYTHING, etc...) and with minimal memory, and voila... the computer booted to the bios and gave me the expected "no boot drive found" error as the hard drive had been disconnected; so the motherboard was fine after all. I proceeded with connecting one piece of hardware at a time and as soon as the hard drive was connected the computer returned to its vegetative state... summary: another bad hard drive; a much easier failure to swallow as these are usually the first to go, but for some reason was preventing the computer from even booting the bios. I decided whatever was wrong with it must be intermittant, so I gave it the old nintendo treatment: smack it around and blow on it for good luck (I clearly had nothing to lose). Booya, clean bootup like nothing had ever happened. At least I was able to buy enough time to buy a new hard drive, clone the old one, and go about my day.
I can't say 100% as I never swapped the motherboards to the original configuration since the second motherboard generated the same symptoms. I should add here though that I've spent all evening troubleshooting the new hard drive. Originally I disconnected the SATA Optiarc Stock CD/DVD RW drive from SATA1 and connected the new hard drive to that connection to facilitate the cloning of the old hard drive. Cloning was uneventful with the exception of an unknown number of unreadable sectors on the old drive (I figured since windows itself was showing no symptoms of being corrupted, it was probably ok, or at least worth a try). Following the cloning, I disconnected both hard drives and reconnected the new drive to SATA0, where the old drive was originally connected and reconnected the CD drive to SATA0. The computer booted beautifully, but then windows attempted to install device drivers for the new disk drive (which I thought was odd), but then failed to find any strangely enough. I figured a reboot was in order, but from then on out the computer failed to reboot; making it to the windows loading screen immediately following the bios load screen, blue-screening for an unreadable split second, then rebooting again. No system diagnostics or recofery options were able to detect or fix anything. I had given up; reconnected both hard drives with the plan to format the new drive and start with a clean windows install. This time windows booted up as expected since I assumed it would boot to the old drive now connected at SATA0 and the new drive again at SATA1. I went to format the disk and realized the new hard drive was now the active hard drive and clearly functional. Any reconnection of the new hard drive to SATA0 resulted in failure to boot, but once reconnected to SATA1 (the CD drive functions fine on SATA0) everything was hunky dory. This has been a trying and confusing issue, but I hope the troubleshooting details help anyone.
UPDATE: Computer back to its old tricks a week after replacing the hard drive... replaced power supply as a hail mary with a Antec 550W... everything back to normal... again... will post again if any further issues. Good news is I almost have enough parts to build a new computer.