|Sounds like one of the hardware components in your PC is taking too long to POST. Not enough information for me to ascertain which component has the issue, but from experience I have found this to often be one of three things:|
1) The hard drive
2) The CMOS battery
3) The Power Supply
I know what I would do in this situation. I would disconnect everything that is not essential to start up the PC (PSU, CPU, RAM and video, plus probably keyboard and mouse). I would then make sure that all of these components (including CPU and cooler) are connected properly, and I would test the start-up speed again.
If the PC boots faster on this minimum config, I would add the other devices (CD/DVD/ hard drive/whatever) one-by-one until I found the device causing the slowdown.
Worth a try - might solve your problem.
If there's no improvement on the minimum config, it sounds like your motherboard or PSU might need looking at. Sounds like your RAM checks out fine, so you might be OK there.