Windows System will not start up

[passingthrough]

I built my system over a year ago and it was running good till today. This morning I checked my emails and no problems.I closed the computer down and went out. Came back after a couple of hours and tried to start it up but it would not start.
The PSU fans, MB lights and other cooling fans including CPU fans came on but the system would not do anything besides that.
I thought it was my PSU which is a Coolermaster 650W extreme power which may be the problem. I bought a 4870 a month ago and was unsure if the PSU would sustain the power requirements of the video card. However I kept on using the PSU and the 4870 installed without any problems.. till today.
I tried to clear the CMOS and set the default setting for the motherboard so I could atleast get into BIOs but to no avail.
I took out my HVR-1600 TV tuner card, my 4870 ( and replaced it with my X800) but no change.
I then took out 3 of the memory modules and just had one 2GB in but no change in the system.
Anyone have any idea what to do as I am at a loss?

My system configuration is
Windows XP / Windows 7 / Ubuntu (multi-booting)
6 GB Memory
Asus P5K
Seagate 1 TB SATA HDD
Western Digital 500 GB SATA HDD
Western Digital 250 GB IDE HDD
X800 video card
DVD/RW drive
Logitech X540 speaker system

[passingthrough]

Finally got it working!