how do you check if a keylogger has been installed on your computer?

[PotKettleBlack]

I am pretty sure one hasn't, but someone has had access to my laptop without my permission or being here. Can I do a quick check, just for peace of mind? If so, how please?

AdAware is meant to be reasonably good at spotting them:
www.lavasoft.com/products/ad_aware_free.php

thank you, will give it a go now.