Rebuilding computer

[CoopCop]

Recently i have bought a new motherboard the SABERTOOTH 990FX/GEN3 R2.0, i realised it will not fit in my computer, so i put my motehr board back in (it has built in standoffs) replugged in all the power supplys connectors and then turn it on.... then it started smoking from the harddrive/CDrom  area.   It wouldent make much sence it if was the harddrive because i did see the little windows 8 logo pop up and it started loading ( this is when i noticed the smoke and turned the machine off) and if it was the CDrom it wouldent make much sence either because it wasn't being used when it first turned on ( as far as im concerned). i have been told to also replace my power supply which i had just bought the other day and is on 115V which is american ( again as far as im concerned)

HELLP!!!!! im not wasting money until i get more suggestions on what to do.

[Geek-9pm]

Let me say something. Here is the best advice I can give, due to present market conditions and your --ahh, mm... apparent lack of skill or attention to detail.

Refurbished Desktops are now going mainstream. The market is now thick will Dell Desktops that have come off lease. These vary from junk to top quality general purpose desktops. Sold without monitors, saves on shipping.
Do not get a USFF unit. Nobody likes them. The standard or reduced Desktop styles a are good. Here is one good one on Amazon.
Used Dell 620 at Amazon.

Dell GX620 Tower, Intel 3.2GHz CPU, 2GB DDR2 Memory, Large 160GB Fast SATA Hard Drive, DVD/CDRW  $103.93 plus shipping

Egghead, Best Buy and others have similar deals. Even Wallchart in USA.

It is better to get a used PC under warranty that invest money in a old thing not working. Been there, done that. I have had better results with refurbished PCs instead of things people just gave me to fix and use.
Not a joke!

EDIT: I have a 520 that runs 64 bit windows 7. My research indicates the 620 is a better choice with the same capabilities. Most vendors have a 90 day warranty.  They come with Windows XP pro licensed by Microsoft.. Windows  7 costs a bit more.

[Lisa_maree]

Hi

You don't say what the old motherboard was just the new one.

Did you remove the hard drive from the case when you were swapping the motherboard ?

Did you reconnect the front usb ports to the motherboard and if so were they plugged in correctly ?

If something smoked then if you remove the motherboard , hard drive and dvd drive you should be able to smell what part smoked or see the damage to the PCB tracks. 

If you can please describe where the damage is and on what part.

As an example : Seagate 500gb 7200.12 hard drive burnt smell on circuit board near power connector .
That and more detail would be very helpful.