PWOER PROBLEM

[AK47]

WHEN I PRESS THE POWER BUTTON ON MY PC THE PC SHOWING NO RESPONCE. AFTER 10 TO 30 MINUTES IT'S START. WHAT'S THE PROBLEM.
PLEASE HELP ME OUT.

PC CONFIG. :
Microsoft Windows XP Professional
Intel Pentium 4, 1700 MHz (4.25 x 400)
Intel Winnipeg D845WN (6 PCI, 1 AGP, 3 DIMM, Audio)
512 MB (SDRAM)
NVIDIA GeForce2 MX 100/200 (64 MB)
BIOS Properties:
Vendor Intel Corp.
Version HV84510A.86A.0038.P10.0204151346
Release Date 04/15/2002
Size 512 KB

[Yaye]

Do you try to change the power transformer?