I'm not sure what that will to to your processor short term. Try to clean it off as best you can, or it could limit the contact between the small prongs and the board. The goo is a heat exchange material. The heat sink/fan on the processor has a small (usually copper) plate that takes heat from the processor, distributes it across the heat sink (metal folds) and blows it away. The goo makes sure that a perfect heat transfer is set up. If you scratched at it at all, I would get some more (it's called thermal paste) and apply it as recommended. A really thin and even layer is all that is necessary, but any debris caught in the paste could cause a total mess. Plus, it will detract from the heat transfer process and shorten the life of your CPU.

Edit: you can use some rubbing alcohol to clean the thermal paste off of the CPU

It sounds as though you got a good deal for a boxed computer. I'd add on another gig of RAM, though. The difference will be noticeable. I'm partial to home-built rigs, so I can't comment that much on it.

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Andrew

1989 Volvo 745- 202K