New PSU or New Desktop Case?

[laptop]

Hello,

Recently I had an opportunity of replacing 300 Wt PSU in my desktop computer.  The old one died with popping sound and a bit of smoke.
I often looked on ebuyer.co.uk and saw quite a number of PSUs there with fantastic specs (but no mention of dimensions not on website nor when calling for their help) and therefore I could never think that replacing it is going to become such a headache.
My old PSU was of these dimensions:   12cm x 8.5cm x 15.0cm (a bit more narrow to be able to fit into a desktop on its side)

Most common PSUs are: 14cm x 8.5cm x 15.0cm

With 3 big harddrives and other staff I would like to replace it with more powerful PSU.  Unfortunately all “mini” PSUs are 300 or less Wt.

Questions in order of preference:
1. Is there any big size desktop case (not mini) that will accommodate a normal PSU ?
2. Did anyone try to modify any existing normal size PSUs to fit into such desktop?
3. Are there any PSUs on ebuyer or anywhere else with dimentions of 12x8.6x15?

Many thanks

[Raptor]

Questions in order of preference:
1. Is there any big size desktop case (not mini) that will accommodate a normal PSU ?
2. Did anyone try to modify any existing normal size PSUs to fit into such desktop?
3. Are there any PSUs on ebuyer or anywhere else with dimentions of 12x8.6x15?

Many thanks

1. See explanation below
2. See explanation below
3.See explanation below

You need to determine wheter your case is AT or ATX.

Use the following article to do so:

Form Factor

Most common form factor now is ATX. All ATX form factor PSUs will fit inside an ATX case.

However, recently, a new form factor for the P1 motherboard power connector has come out which is called ATX 2.0. This will not always fit on ATX 1.0 mainboards. Be careful when obtaining a PSU and be certain to avoid ATX 2.0 unless a converter cable can also be bought. (24 to 20 pin)

AT is heavily outdated and these products are most likely not being sold in stores anymore.

Install a PSU of at least 400 watt or more for system stability. Do not buy the cheapest available.