It takes 2 minutes to open a one-page PDF. When double clicking on the PDF, Adobe reader opens but the PDF content doesn't display. It says 'Not responding' for about 2 minutes before it can display the content of the PDF. The PDF is just a one page file. It can be opened by other versions of adobe reader instantly. It can also be opened instantly on another PC which is also W7 64 and Adobe reader X.

These are the various methods for resolving the slow opening and browsing of PDF documents using Adobe Reader:

1. Use an alternative reader such as nitroPDF/FoxIt Reader/Firefox Browser
2. Uninstall/Re-install
3. Go to Edit / preferences / general - the uncheck box "Enable protected mode at startup" This got rid of the lag in opening adobe docs.
   The setting is now under the Security (Enhanced) Selection. Just uncheck the Protected mode and that will fix the SLOW ISSUE!
4. Go to Edit / Preferences / 3D & Multimedia - then uncheck box "Enable hardware rendering for legacy video cards" This got rid of the lag in opening adobe docs.
5. Closing the Tools Pane sped it up immensely!

Taken from adobe reader X very slow to open some PDF under windows 7 64-bit - Windows 7 Help Forums