The PSU went out on my old desktop. Son built up the system then took off to Bermuda for an extended vacation. Don't know the brand but the model number on the PSU is WT300U. Can ANYONE identify the make so I can search for a replacement?There are basically only 2 sizes when it comes to PSU's...ATX and Mini ATX.
If in doubt either measure it and or take it with you when CHOOSING a replacement.There are great advantages in living on a mountain top in a very rural area but shopping is not one of them. I will have to order on line, returning wrong parts means a 100 mile round trip to the nearest UPS office.  I recently installed a new power supply in a retired friend's old HP and it was a special part, it  had to be ordered from HP, an old  (non sata capable) 188 watt PSU that cost $85. I had a computer shop in a neighboring community check it out and do the ordering. Nothing in their shop would fit. The PSU in my desktop is rated at 300watts but is very small. I have a new 450 watt supply but the access holes do not match the desktop case. I'm afraid that cutting new access holes in the case would spray metal CHIPS into the circuits. Based on your reply I'll order a mini and hope for the best. What is the make/model/wattage of the PSU. It will be listed on it. It will probably say ATX on it somewhere as well, but you need to make sure. If it is not a name brand machine (HP, Compaq, etc.) there probably will not be an ISSUE. 

Nothing turned up on Google with the info provided. Can you take a picture?