Dell forum: Studio XPS 435MT unable to boot

To begin with, the XPS 435MT runs Win 7 x64 just fine. I have been using Win 7 Pro since it was released with no issues.

On the night of July 26, 2012 I shut my system down due to approaching thunderstorms even though I use a UPS that offers much better overload/underload protection than the run of the mill surge protector power strip solution. The next morning my 435MT would not boot. The power button LED would flash amber once then nothing would happen.

Checked the back of the 435MT and the green LED on the power supply was illuminated green. Using an old laptop, I did a search online and found a Dell forum thread that described the same issues I was experiencing. The majority of the solutions pointed to replacing the PSU due to degradation in output as a result of aging. So, even though the original PSU still worked it didn't produce enough power to boot the system.

The stock PSU is a Delta model DPS-360FB-1A which only produces a maximum of 300W on the two 12V rails combined. I ordered an OCZ ModXStream Pro 600W from Newegg for $50. Once installed, the 435MT booted up with no problem. Just about any ATX form factor PSU will fit. The OCZ600MXSP is about 1" longer than the stock unit at 6.5" (165mm) and fit just fine. It also has a downward facing 140mm fan that runs quietly as well as providing increased cooling.

In summary, the stock PSU in the XPS 435MT is barely adequate to the task when new and after a couple of years degrades to a point where it will no longer provide enough power to boot the system. Rather than waste time and money troubleshooting the motherboard, hard disks, memory, etc, replacing the PSU is quick and relatively easy to do. I would suggest a PSU that is rated to at least 450W.