Mine has the same problem: Intel Desktop Board DP35DP.
Fans are blowing for about 1 sec, then he reboots itself again and again...
First try default setting in bios by removing the CMOS battery on the mobo, and unplugging the power supply's power cable for a few minutes.
Is your your CPU fan ok? Did you change the RAM voltage? Is it possible to try to reboot this machine with another graphics card ?
Yes I've changed my RAM voltage !!!
And I've tried to reset BIOS settings by removing the battery but nothing happened !!!!