Hi Helixus,

Yes, obviously this model takes a standard PSU. Did you already get the GTX 560?

Yes.... I got it a while back.

Can I ask why this model is designed not for upgrades? Or is it all Dell models?

Helixus,

Guess I was not clear. The Inspiron 620 can be upgraded to any standard ATX power supply.

Oh...I guess I misunderstood. Okay then, the issue is then why have the ones tried using wont work? Do I need to do something specifically before I attempt to install a new one. Because with both new ones that Ive tried, the computer wont start with either one. But they work fine when I tested them on my fathers computer. Gateway desktop...not sure which model but its an i3 motherboard as well.

The PSUs ive tried : Corsair GS700, Thermaltake TR2 600

Just so I've covered everything, have you verified that the system works with the original power supply?

Yes, it works just fine with the original.

All the Dells I've worked with since 2002 have had standard power supplies. I'm puzzled as to why the two you've bought won't work, unless they've been connected incorrectly.

Cant*, sorry for double post.

Idk either. I dont get how I could connect them incorrectly.... the plugs are shapped to where you really can screw up. Plus as I mentioned I got them to work in a different computer.

I'm not sure what else I can suggest. Corsair is one of the brands we recommend, and that GS700 should be more than adequate for your needs. Apart from checking the connections, there's not much else that can go wrong.