Windows hangs on boot.

Hi everybody I was hoping you could help with a perplexing situation I have on my hands.

Since a few hours ago my Pc wont start.
When i rebooted it stayed for ever on that glowing-pulsing quad-colour thingy that windows 7 shows briefly while booting, and never moved ahead to get into windows desktop

After a couple of failed attempts I decided to try logging in at 'safe mode'. even this didn't work. The boot sequence seems to be hanging after trying to load the CLASSPNP.SYS driver.

and yes i read the various posts and Windows 7 hangs on startup this guide as well.

So i decided to use the Win7 disk to perform a repair. I even have a rescue disk, actually two as I set the last one up just a week ago, and i even have a full image backup on an external disk, to restore if everything else fails.

problem is, when i try to boot from the DVD or the repair disk, the following happens:

I get the option to boot from the DVD. >> i choose to do so.
Then i get the usual message that files are being loaded or copied
Then i get the small glowing bar that moves left to right, the usual image preparing us to enter the setup environment and then:

BLACK goes the screen, and the NUMLOCK key locks ( you cannot change ts state..) which is usually a clear indication the Pc has hanged badly.

I tried with two different windows 7 disks.
also with two windows 7 Repair Disks.

it is always the same.

Then I tried disconnecting everything from the Pc apart from the boot SSD.
even all external connections.
USB, eSata, even the mouse and left only a keyboard.

The same things is happening

I even changed keyboards, back to a plain vanilla Ps2 KB.

Nada.

I'mout of ideas atm, any help would be greatly appreciated.

PS.
I would like to point out that till 3-4 days ago the PC was working like a clock for around 3 months.

Then i started having frequent problems with my Bluetooth Wireless Logitech keyboard and mouse. The signal would get lost, even though both had batteries over 50%.

sometimes i was able to correct this, by having the Logitech software re-detect the keyboard and mouse by pressing a reset button on the usb-blue-tooth receiver.

4-5 times I had to hard-reset the Pc though as this didn't work and i was left with a non-responding Pc on my hands. I'm guessing these 4-5 hard resets might had something to do with my current problems, even though all these stopped since yesterday when i swapped the wireless keyboard for a regular USB one.