I wandered whether there was an alternative to Adobe, just to read pdf documents because, as per Jayday, it does take up a lot of disk space(for something I don't use that often)and takes an age to open.
P.S.I've scanned with Spybot and AdAware SE after I installed it, and it seems to be malware free.
Top link... Very good. It's noticable how quicker your pdfs open once you've optimised Adobe Acrobat. If you ever use a PDF which uses a feature which has been disabled, it's very easy to revert to the original settings in Acrobat!