System Dont Boot.. Again..lol

Hmm heres my problem in the moring all worked right. so i decide to mod a xbox controller to use it on computer. i found a tutorial and do the modification i pluged and all is alright. but the controlet wire ar getting hot so i changed for another controler.. no heat issue so i install xbdc drivers and rebootted
and now at winxp logon screen the computer shut down..

so i tried to boot it again.. nothing i unplug the usb controler.. and nothing again. so i unplug all and only keep the video card. system boot but nothing on screen. so i tested my card on my other computer and worked fine,ram too hdd too. so now i suspect My Mother Board ATX female molex. or my 300watt psu male... after some tried the system do no start like if it as not source.. so i push down the atx male and the card booted but then reboot about 2 or 3 times every second. so i tried psu on another mother board and he works.. dont know what to do.

EDIT: Theres a small beep i can hear if i plug the speaker
but this beep about 2 times per sec fan turn and stop the power supply fan too :s my Dual Lan slot 2 light is flashing too

Ps i dont see any crammed solder on the card

Please if someone ever have the same issue i hope he can help me for this. lol ****in new computer about only one month used..

Msi NeoII Platinum
A64 S939 3200+