COMPUTER RESTARTS AUTOMATICALLY !! pls. help

Hello Gods of Computers..
Here's what my problem is:

Yesterday, my computer is really working great then just this morning, After i open my pc, there is some options available and after i choose each of them my computer restarts and NO BLUE SCREEN APPEARS or ERROR SCREEN;

there is just a message that maybe my computer was turned off unexpectedly...

in a short term that is the guide that you will see when you see this:

safe mode (doesn't work)
safe mode in command prompt (also doesn't work)
last known good configuration (after a long waiting of loading still doesn't work)

i almost tried all of them but not each of them are working.


i already checked all slots and plugs they're all connected well so i guess that is not connected right!?

i already checked from the BIOS and they're all doing well,

noted that i have a PC Temp. of 40 degree Celsius

Here is also my computer stats if this can help:

A Brand New Computer just bought 4 days after with a specs of:

AMD Sempron Processor LE-1250, 1GB DDR2 RAM, with a built in video card max shared to 256MB.

so, is there anyone knows how to get past out of this problem?

please help me... ASAP.. thnx =)