Try going to Start -> All Programs -> CCleaner.

You can also hit Windows+R (or Start -> Run) and type in CCleaner and click OK.

Piriform, the developers of CCleaner makes software that lean, optimize, defrag, recover deleted files and deliver system information. CCleaner, the flagship product has been downloaded more than 2 billion times.

rb.gy/ejm0nd

Try going to Start -> All Programs -> CCleaner.

You can also hit Windows+R (or Start -> Run) and type in CCleaner and click OK.

I have included a link to Piriform's docs in the Docs section.

will ccleaner work on a 64-bit windows instillation

I assume you mean Comodo System Cleaner. it is not as comprehensive as cCleaner and does not have a uninstall utility or a way to block startup programs as cCleaner does. I run cCleaner and highly recommend it. It is very safe to use and is the best free one you can get.