With regard to 'Adobe Reader' . . .
There's nothing 'wrong' with using Adobe Reader for viewing PDF files. However it is incredibly cumbersome an it can take ages to load big files. The current issue of Web User magazine lists it as one of the 'top 10' (or should that be 'bottom ten'?) programs in an article entitled 'The Worst Software Ever'.
The most frequently recommended alternative (here on AB) is Foxit but the Web User article suggests using Sumatra PDF instead. I installed it myself yesterday and I'm
very impressed with the difference. (Big PDFs, that were taking several minutes to download and open with Adobe Reader, now open almost instantaneously with Sumatra PDF). If you fancy trying it, the download is here:
http://download.cnet.com/Sumatra-PDF/3000-18497_4-10698785.html
(When you get to the installation dialog, click on the button at the bottom left which allows you to choose your installation options before clicking n the 'Install' button. Then tick the box which sets Sumatra PDF to be your default PDF viewer).