[WORKAROUND] “Adobe Reader” version 7.0.5 hangs in Firefox 1.0 and 1.5, using all CPU
If you run “Adobe Reader” (no longer called Acrobat Reader as of version 6) in Firefox 1.5 (or 1.0) in Windows XP, you may discover that it uses all CPU when opening a PDF doc.
Uninstall Adobe Reader from Control Panel:Add/Remove Programs, and download an old version like version 5 of Acrobat Reader here:
http://www.adobe.com/products/acrobat/readstep2_allversions.html
Thanks to Joshua Burke for suggesting the solution here: http://www.askbobrankin.com/inbox/stumper_firefox_consumes_the_cpu.html