Well, that almost certainly makes this a hardware problem... You're going to need to start testing each device and find out where the fault is. I would start with the power supply your replaced - it could very likely be giving too much or too little power and this could potentially be causing more damage.
Open your machine and get a look at your motherboard. There should be the model printed on the board - look carefully along edges, behind drives & wires, between card slots - it should be written somewhere unless it's a generic (in which case it would be on the underside and you won't see it unless you dismount the board). If you see the number, post it.
If you can't identify a model number this way... Is this a Dell, HP, Gateway or some major manufacturer? The Model Number of the manufacturer's line should be on the side of the computer, printed on a sticker. We can look up the mobo from the company's specs for the machine. If it's a laptop, it would be on the underside of the machine. If you find this, post it.
Also post the specs of the new power adapter - wattage, voltage, make, model etc.
It's more than possible that whatever made the old adapter explode like that also damaged the mobo or other components of your system. Assuming your new power supply is OK, I'd do a diagnostic on your Hard Drive, then your RAM. If these check out, start checking for visible damage on your video card and if you have a known working spare, switch it out to test that. Last thing I'd check is removing the heat sink and checking that your CPU is OK with no scorching around the area - the fire would have been very close to it, as the power adapter is generally mounted just above the motherboard, near the CPU and heatsink.
If you need specific help with the above steps, just post questions and let us know. But, I honestly think that unless you're up for a ton of trouble-shooting devices and general jiggery pokery, you may be better off just buying a new computer. I love doing this kind of thing, myself, but not everyone is up for it - it gets a bit tedious and can be frustrating unless you like doing it.
Edited by n3ko, 22 September 2009 - 07:53 AM.