NeeD help regarding display

Hi guys,

I just started my PC after a while & it turns ON, lights turn on, but there is NO Display on Monitor but after 10 min. (aproxi.) display running.

I did some research on Google about this issue & did a few things.

1). I removed all the hardware, except processor & power supply. Turned On, but same issue.
2). I tried after removing ram, & then by switching ram slot, but still no use.
3). I removed my HD 3450 512MB graphics card & plugged monitor in Built-In Monitor port & Vica versa (In Graphics Card), but no use.
4). I removed hard disk & DVD rom & changed their power cords, but no use.
5). I removed the computer cord, & pressed & hold the "ON" button for 30 to 60 seconds, but no use.

Actually when I turned on, it took a long time to get to display & then window was also working weird, then I restarted a couple of time & I though it was my hard disk, (who sometimes have power cord issue that works fine if we change it, but its not that).
Anyone please let me know how can i fix??