forget the bloated adobe reader use foxit reader instead.
http://www.foxitsoftware.com/pdf/rd_intro.php
seems like you have got a browser hijacker installed.
I suggest you run a scan with malwarebytes .
you can get malwarebytes here,
this is a direct download link
so you should have no trouble getting it.
click on this link ↓ and then select run.
http://www.malwarebytes.org/affiliates/2-spyware/mbam-setup.exe
install it preferably to your desktop, update it,
then run a full scan and remove everything it finds.
some viruses will try to disable it
so if malwarebytes will not startup
then go into the folder it is in and rename the mbam file to XXX
then double click on the file you just renamed to start it up.
after you have used malwarebytes then do this online scan.
to make sure you have nothing else hiding away.
http://www.bitdefender.com/scan8/ie.html
preferably in safe mode with networking.
☺