Adding power to my computer

Here is my computer:

Any reason why I can’t replace the power supply and add another hard drive and and lightscribe DVD burner?

I’m thinking about this power supply

It looks like some of the variants of that model don’t use ATX form factor. Open up and check the sticker for identification.

Well its a BTX case but the motherboard uses ATX power

I doubt you need to change the power supply to do that. If you had bought the computer with those additional drives it probably would have come with the same power supply.

I have a similar gateway machine, and was able to add two additional HD’s (one PATA, one SATA) without any problems with the system.

I don’t have any additional power connectors as they are being used for the 7900 gt video card.

You can get power splitters pretty cheap - just try to balance the load between the different leads.

Well its a 300 watt power supply and I calculate my current power needs are at 278 watt. I don’t think throwing another couple of drives is a good thing to do.

I calculate my current power needs are at 278 watt

Calculation, shmalculation. Have you MEASURED the actual power usage?