CCleaner 'stopping' at 18%

Hi, I've used CCleaner for a while now and had no complaints, but recently it's been playing up. Whenever I run it it 'stops' at 18%. The little icon is still spi ning round but nothing appears to be happening. It's been like this for over half an hour now. All it says is:

System

Temporary Files

C:\Documents and Settings\Owner\Local Settings\Temp\NVE1B.tmp

Try rebooting. This appears to be a temp file, i.e. it might be in use.

Will do. Thanks.