No Audio

Hello ppl,

Problem: I was watching a movie on my computer when suddenly my system switched off. I tried starting it again, but the system would not start. Suspecting my SMPS, I replaced my 450W SMPS with a 230W SMPS. The sstem booted but now there is no sound.

Here is what i've tried so far:
I tried reinstalling the audio driver, but it does not allow me to install the driver.
I also have Ubuntu installed and there is no sound there as well

I feel the motherboard is underpowered. My graphic card itself recommends a minimum power supply of 350W. On top of that, I have 2 HDD. Everytime I start windows I get a "found new hardware notification" (it is detecting the audio card) but the driver is not getting installed. Pls advice how to proceed.

Is it possible that my audio card is fried! :( pls help!

Here's my computer specs:

Processor: Intel Pentium D (Dual Core)
Mother Board: Intel Essential Series D946GZIS
HDD: Primary: Seagate Barracuda 250 GB (SATA)
Secondary: Western Digital (WD) Green Caviar 1 TB (SATA)
Graphics: XFX GeForce 8400 GS 512 MB
Optical Drive: SONY DVD RW AW-G170A
Operating System: Microsoft Windows XP Professional SP3
Current SMPS: VIP 400R (230W)