Got home and computer wont work

What are the system specs? Your PSU may be too weak to power your system, but it could still power your sister's system. So, I wouldn't rule out the PSU just yet.

Its BIOSTAR TFORCE TA790GX 128M mobo.
AMD Phenom II X4 940
Radeon 4770
640GB HD
DVD Drive

PSU is an Antec EarthWatts EA650 650W

That's a pretty good PSU. It should have no problem powering your system.

Try using a different outlet and power cord.

Tried that as well. No luck . Have tried 3 different cords and at different outlets in different rooms.  

At this point, I would suggest breedboarding.

Remove the board and place it next to the case on a piece of cardboard. Connect the PSU, power switch, and 1 stick of RAM.

If it powers up, add the video card.

Dang.. This sucks. hah. I'll have to do this tomorrow though.. too tired tonight.

BTW.. Is there any kind of warranty on the motherboard or anything? If the MOBO is the problem that is.

I just don't see why it suddenly quit after 5 months of flawless computing. Never had freezes.. never had any problems. Just get home and its gone.  

Authorized distributors should offer a 1 year warranty. If not, Biostar will back it with a 1 year manufacturer's warranty.
http://www.biostar-usa.com/app/en-us/support/rma.php

Oh ok. I bought it all at newegg.

Good thing for you. Newegg is amazing with customer support. If you decide to RMA the board, you can email newegg, and they usually will send a prepaid shipping label, so you don't have to pay for shipping either.

RMA is not available because all of it was purchased over 30 days ago.. So I guess I need to go to the OEM?

Then the link that I provided to Biostar will back the RMA.

Ok. I got a RMA #... But they tell me to ship it "Freight Prepaid"... How do I do this?

I mean.. when I go to ship it.. and tell them "Freight Prepaid".. they aren't just going to let me ship it for free are they? Surely Biostar would have had me print off a shipping label but I guess not.. Anyone with experience here fill me in please..

You can ask them for a prepaid shipping label. It will usually come in an email. If not, they expect you to ship it to them, at your cost.

Ok. Got the motherboard.. and it works.. but now, the CPU looks dead, along with the harddrive and dvd drive.. And I am not sure about the ram yet. The videocard fan started spinning, but I haven't been able to test to see if it works properly. So I am RMAing the hdd and cpu. Hopefully I can test the ram and videocard soon enough to know what I need to do there. I don't know what happened, but the whole computer took a major blow.. not sure what would cause that. Hope to have it back and running sometime in January.

Ok, you may want to double check your connections. That's a lot of hardware to die at the same time.

Double check the 4/8 pin CPU power. Without that, your CPU doesn't get power, and the board won't POST.

What explains the harddrive and dvd drive going out as well? I agree.. that is a lot of hardware to go out at once.

I have went through and checked the wiring.. have tried 2 different power supplies.

Also.. the CPU does get hot.. so its getting power. The fan works (of course its plugged into the motheboard.. so doesnt really matter). But the CPu does get hot.. just no signal. No beeps or anything.  

Odd.. Just checked again and now the dvd drive works.. it pops open and shut. Wasn't doing that earlier. Don't know how to take that.. but anyway.

Ok.. Now I can also hear my HDD spinning (checked in another pc and didnt work).. this is odd.

Biostar told me no beeps means cpu/mobo.. So its lookin like cpu right now.

Another update::::
Ok. About the dvd drive. It works.. but ONLY when its not plugged into the motherboard. I can have the IDE cable running from the dvd drive to nothing.. and it works.. but as soon as I plug the other side into the mobo, it quits working.

The hd is working.. I hear it going.

The cpu gets hot.. and works as you would think. But I have no true way to test it.

Could I have been sent another bad mobo by Biostar? Its making me want to just say forget it.. and buy a different motherboard board.. maybe a Gigabyte or something. I don't want to spend $100+ though. Ive tried getting it to post with the onboard gfx and also the Radeon 4770 gfx card. Same result.

----Another Update-- trying to not keep replying to thread---
Put harddrive in another pc.. its spins up and stuff.. but when its hooked into the computer. The computer doesn't recognize my other Sata drive. Only the IDE drive. When I unhook the hdd (from broke pc).. the computer recognizes the original sata drive. THe crazy thing about this one is that the bios recognizes the original sata drive (never sees the one from broke pc).. but stll Windows doesn't see it.

I am just gonna go ahead and RMA the cpu and hdd. I've already got RMA #s... Just gotta pack em up and ship it off.

You either have a bad IDE cable, incorrect jumper settings, or your BIOS isn't configured right.

The fact that the DVD drive only works when the IDE cable is unplugged, suggests a bad cable. The drive can have power to open and close the tray, but without the IDE cable, it can't transfer data/won't be recognized by windows.

Since you are using SATA and IDE devices, the BIOS needs to be configured to use both.

I tried another ide cable. Same thing. I can't configure the Bios if I never can get into it.. and the jumper settings are no different than before when the computer worked great.

Its a big mess.. I'll work it out soon enough hopefully

Ok. Down to basics....

Remove the board from the case. Place it on a piece of cardboard next to the case. Plug in the PSU, 1 stick of RAM, and power switch. Try booting with only that hardware. If you POST, add the video card. If you're still good, add the hard drive. Keep adding hardware until it stops working. Then you'll know what is causing the problem.