Keyboard Problem (cant scroll down)

Hi,
I am a beginner so i will explain the problem the best i can.

Up to a couple of weeks ago, i was always able to use the down/up arrorws on the keyboard to scroll down on a web page. Now I must hit F7 evertime I want use the down arrow on the keyboard and must do this for every page.

Curently, I cant do this and must use the mouse and place it on the arrows on the window to move the web page which is must more time consuming.

HELPFUL Information
Right around the time this problem arose I installed a new version of internet explorer toolbar. I have had various problems since I have installed this.

do to another problem, I ran my hands across my keyboard several times because computer was freeing up. i was thinking perhaps i locked something on the keyboard therefore i cant scroll down properly.

Any help will be appreciated.
Thanks you

hmmmm there cud be many reasons for this..im no expert.. but sumtimes wen ya download new programs it can conflict wiv other stuff on ya pc..u cud do a system restore to an earlyer date or jus uninstall the program.. or buy a new keyboard..as for it lockin i dont no..iv got a stupid usa keyboard so sum of my stuff is different which is a pain..like i say im no expert so not much help im affraid..im learnin as i go..try unplugin ya keyboard an then plug it back in..wen ya pc is off..

I use mouse scroll too... so don't fink i can help either lol