You may have malware in your computer. I have the same problem, it always redirect to other site and ask me to download its program. It does slow down a lot. I reset Firefox which helps, but I still have the problem. It’s difficult for me to find a program which runs on XP.
Any suggestion???
Step 3.3 : Reset Mozilla Firefox
Open Firefox and then go the Helpmenu (Press “F10” key once to active Menu bar)
Go to Help menu then click on “Troubleshooting information”
Note: you can also open this page in this ways, open Firefox then type this command in the address bar “about:support” (without quote) and then hit enter or OK.
You will get a page “Troubleshooting information” page, here you will get “Reset Firefox” option in the right side of the page.
Click on Reset Firefox option. and follow their instruction to reset.
Now your Mozilla Firefox has been Restored to default settings.
AdwCleaner helped me get rid of Coupon Printer and some other crapware that was on my wife’s computer.
http://lifehacker.com/adwcleaner-removes-toolbars-and-other-malware-in-one-cl-734204747