Half installed SP2

Hi

I was installing SP2 without reading the requirements and didn’t realise I would need a whopping 1.8 gig free for a 70mb file. So the install has taken up all my hdd space without finalising. How can I get rid of the already installed files. I have tracked down the files (I think) in C:\WINDOWS\SoftwareDistribution\Download\6ca7b3a8efd5a9b6f87fff395a2eb989
but the spuninst file will not work.

Any help much appreciated.