Okay, apologies of this is off-topic or even off-forum but I'm desperate!

My CPU originally came with a fan with a thermal pad (retail boxed AMD Athlon XP 2000+). In my folly I thought an Akasa 825 fan would be a good thing to have. It comes with thermal silver paste. Just pop a blob on the CPU , smooth it out into a thin layer with a business card, pop on the fan and the job's done.

Enter a world of grief as the machine goes into a reboot cycle once I power up and try to boot into linux (or any other inferior OS) .I go into the bios health check screen and I can see the CPU temp raise rapidly from 50C through 75C, watch as the motherboards (AN7) CPU thermal throttling kicks in and the temp goes down to 50C and then climbs again. Dismantle PC and try again. With similar results.

The instructions say don't put too much on, but how much is enough (I've only got a small tube/syringe of the stuff to play with). I've already been down Maplin's to get a bottle of TIM-clean to make sure the heatsink base and CPU die are squeaky clean. Should I try and find a source of thermal pads, since that seemd to work fine last time (I didn't spot any at Maplin).

With the amount of paste you get from a shop you can install dozens of coolers. Take the amount of paste which fits on the corner of your business card and spread it evenly. Apply a small amount of pressure when spreading and remove what's too much. It only has to be a really thin layer of paste. Make sure the cooler is mounted flat on top of the processor.

Thermal pads retain more heat than paste, but whether you use silver paste or regular paste doesn't really matter IMO. As long as it transfer the heat to the cooler.

Try some other paste? A lot of "silver" paste doens't contain any silver anyway. I suppose the cooler is not at fault here, since it seems to be a good model.

Really thin is the key. To much can be counter productive.
Besides making sure that the HS is flat, make sure that it's squared and in the right position on your CPU. That way it's not trying to twist your CPU in order to line up with the snap downs. Also, since your going to have the HSF off anyways, take the CPU out and re-seat it. I've seen all kinds of problems with CPU's that aren't seated properly.

Do not use both the thermal pad and the heat sink grease. With heat sink grease or paste you have to take off your heat sink every few months because the heat sink grease or paste dries up. For a permanment application and easy to apply, use thermal pad. Thermal pads work as well as the heat sink grease or paste. In many cases thermal pads works better than heat sink grease because thermal pads minimize installation errors.

For heat sink grease, about a milliliter (mL) is enough.

The best heatsink for AMD and Intel is Zalman's copper flower models.

Thanks guys. I'll try and find a thermal pad and see if I can get a result.

Edit: Akasa do a 5-pack of replacement thermal pads. I'll pick up a pack and have another go tomorrow evening.