I need real photo of yours.
Try this algorithm:
1) disconnect power cord
2) disconnect all HDDs and optical drives
3) remove all DIMMs and CMOS Battery
4) install your Q6600
5) wait 10 mins
6) press and hold power button for 30 sec.
7) install CMOS Battery and one DIMM only in first slot.
8) connect power cord and try to power on.
Thank you soo much it works again!
I hope the X5460 will work too with the Mod Sticker.
Greats from Germany