I'm new to this game so take my suggestions with a grain of salt until someone else will confirm it but i suggest the following:
create a virtual computer on your computer. Microsoft has one called microsoft virtual pc. . i believe it to be free. With a new virtual machine you will have a new mac address. Double check it but i'm pretty sure its the case. Not to mention you will have a brand new computer with its own 'fingerprint'. I suggest you use a different user agent, and add a few plugins or nuiances in other ways (text fonts) to that machine to give it a semi-unique fingerprint. I bet there bots like that. Furthermore no more worrying about cookies/flash etc. its all covered by the new machine.
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