Brand new computer freezeing

[Lejend]

Alright so i currently just bought an ASUS computer:

Windows 7 Os
dual core 2.6
6 gb ram
Nvidia 9800 gt

if you need to know anything else let me know.

Couple of things happens.
All of which didnt start till i upgraded to the 9800 gt.
Sometimes ill start the computer up and it will just sit in black screen.
ill wait for a second and nothing.But when i go to turn it off it automatically shuts off right when i touch the button. i dont have to hold it as if the computer froze or anything. Also periodically the computer will freeze, i tried to find similar posts regarding my issue but everyone seems to say there comp freezes while playing games. But if mine is going to freeze. its only right after windows 7 loads and the desktop screen just pops up. Other then that the only other time it freezes is if i let it go past the screen saver and it goes to power saving mode . It doesnt happen all the time but ill click mouse so it will wake up and it will be frozen or screen will stay black. Any help would be very much appreciated. ty

 

[Hefemeister]

What psu do you have?
Have you installed the latest video drivers?
If you had an ATI card prior did you remove those drivers?

 

[Lejend]

If there's any other way to find psu model without opening comp let me know if not you will have to give me a few minutes.

I had an nvidia 8400 gs prior and did uninstall drivers, I also check for updates every day

are we looking for my out put or input on the ps?

input 115v - /6a , 230v - /3a , 50hz-60 hz

output peak 300w rated 250 w

 

[wafflehammer]

upgrade the power supply to a good brand 400w

 

[Lejend]

alright ty.