Unable to unzip 2.6.2

Hi folks,
I have seen the upgrade to 2.6.2 over the last few days in my admin panel on my blog and then today I thought, Right, I am sick and tired of seeing that I’ll upgrade to it. But when I try to unzip it on my local computer it fails and falls over, I have tried in Windows Vista with the built in zip archiver AND with Winzip, I have cleared out my temp files, restarted my computer and all of the usual suspects to no avail. Any help or tips would be of great help.

Thanks
Hugh