I have a home built system and i'm looking to upgrade the PSU to 450W (or more) PSU. The case is a microATX minitower (dimensions are 7"Wx16"Lx15"H)
The problem is that I don't know which type of power supply to buy for this type of case. All the power supplies I have looked at so far say ATX or ATX12 so I'm not sure that those will fit in my case. Is there a special type of power supply for microATX cases?
Can I even upgrade the PSU? or should I buy a new case altogether?
(BTW the new PSU is for a new graphics card I'm getting)
I would remove the power supply from your case and inspect and measure it. Newegg has excellent diagrams with measurements; it won't be hard to compare and come up with a replacement. Or you can post a picture or the make and model number of your case.
You should measure the size of the power supply in the case already to make sure that the new one will fit. Although some microATX cases have room for a regular ATX PS, most require you to get a microATX PS.