I would strip the cpu from the HS+F and see if there is any damage. Look for smoke or even heat damage on the top of the chip. Also check the pins. Any signs around the base of the motherboard socket. This may give you a clue.
if not, then the likely hood would be a dud board. Even so, just because the PSU has the fans running, it may still be worth just "bridging" a good PSU over, just to be sure.
As you say a replacement board for the cpu is relatively cheap ( £20+ ) and might not be a bad idea. They do come with loads of extra features and usually have a decent upgrade value.
Where is your approximate location in the UK. If you are near, you could drop the 2400+ in my athlon board. Or you may be close to another member who would not mind.
I don't think you have properly identified your problem yet.
It could be your PSU, just because the fans spin don't mean its all working. I've had this before on more than one occation.
Disconnect everything from the mobo, cpu, cards, memory, HD/CD. Then put it back together one bit at a time and try to boot with each bit in. Obviously it won't boot to windows but you should get to bios (might just be beeps before the gfx goes in).
just because the lights are flashing and the fans are running doesn't mean that the PSU is not at fault. an under powered PSU will give enough power to get fans running (dont know the full specs on PSU mobo connectors) and some lights but still not have enough power to kick start the whole system ( know from experience ).
it might be a pain not to have the pc up and running but it does mean saving money on buying something that you didn't need.