Windows 7: Booting crash

I booted my PC last week no problems, wen't to open my browser and everything froze. I had to then force shut down with the power button. Ever since then, I've tried to boot the system and no matter what I do it freezes before I get to the log-on screen.

Previous problems:

Faulty hard drive (replaced)
Faulty motherboard (replaced)
Faulty RAM (DRAM LED on motherboard) no longer lit up in red

Freezes on:



Safe Mode(s) - CLASSPNP file
Startup Repair (Attempting Repairs - have left for over 5hrs before)
Starting Windows animation

Have tried:

All of the above
Booting from Windows 7 disk
Windows Diagnostics tool

Obviously I must have some sort of nasty bug because this has all of a sudden happened. Have searched Google and many forums for answers but no luck. I am rapidly running out of options!

Any help much appreciated.

I suggest starting all troubleshooting with the following diagnostic tests. They'll save you a lot of time and heartache if there is a hardware failure, and you'll have the disks on hand in case you need them in the future:
Once you've let us know the results of the HDD and memory test, we can move on from there.

Hi,

Thanks for the fast response. I have run the diagnostics tool but again I got another freeze. I would run the online test but it won't let me anywhere near the log on screen so I am very limited as to what I can do with it (currently using a different PC)

Try opening the side of the case and point a house fan into it at top speed.
See if that lessens the freezing.

Nope, my PC is dust free inside.

Still, point the fan at the video card to see if it helps to cool it down. For example, if the cooler isn't working properly, the house fan will cool the entire card - which should lessen the problems. On the reverse end - if the fan doesn't reduce the problems, then we can rule out overheating as a problem.

Over heating is definitely not an issue. My PC case has many, some large, fans. Everything is kept very cool, clean and tidy.

Do the Starting Windows dancing balls just stop dead?

The Windows 'flags' continue to glow (on & off) but does not go any further.