browser hangs

I have been experiencing a problem while browsing the internet. While scrolling on a page or clicking a link, it will 'hang' (the spinning circle) for a while ( a few seconds up to a minute or two) and then will usually progress to the next page or be able to continue scrolling the the current page. This has been happening for about a month. It occurs on both Firefox and IE. I am running Vista 32 bit with all the updates, 2.1 Ghz Dual Core AMD, 2G ram . It doesn't seem to matter what page I'm viewing as to when it 'hangs' and it happens at different intervals. I have run Malwarebytes and it found nothing. Also my anti virus reports nothing. This is very annoying and really slows down the searching. It does not affect other use of the computer.
I don't believe it is a problem with the ISP or router, since my other computers do not experience this problem.
I have searched for solutions but haven't found anything although there are others that report the problem.
Any ideas or suggestions???
Thanks

Download CCleaner (You can easy find it on Google) and Run it.

Mark this :
Temporary Internet Files
History
Index .dat Files
Last Download Location

And if you want Cookies

Than go to Application tab and mark for Mozilla :
Download History
Internet Cache
Internet History

And if you want Cookies and Saved Infromations

Click on Analyze button, than click on Run Cleaner

I ran CCleaner having it check and fix those items you suggested. As I am typing this it is hanging now. It sounds as though the fan comes on when it does hang.
Should I go ahead and do the registry check and fix issues?
Thanks

Hello,

Your computer is experiencing a overheating issue. Make sure that there is proper ventilation in your computer and no dust is covering the ventilation.

Thanks, I will check to see if there is excessive dust in the machine. There is plenty of space around the vents. Will try to get more air moving and see if that helps.

I checked inside and there was very little dust on the fan/heatsink but cleaned it anyway. The vents are clear and there is space around the tower so airflow is not blocked.
Still hangs when on web pages but not when using other applications.
Any other ideas???
Thanks for the suggestions so far.

Hello,

Please try to completely uninstall Firefox:

http://www.geekpolice.net/tutorials-guides-f13/completely-uninstall-firefox-t14503.htm

Re-install it and see if it still occurs.

Thanks for another suggestion. I'll give that a try but it also happens with IE. Will/Can that be removed and reinstalled?

Hello,

I'm not sure, it may just be the speed of your computer?

Thought I'd let you know that I tried the reinstall of Firefox. Didn't seem to help. I received notice that my ISP provided anti-virus was expired (which was wrong, but I couldn't convince the program otherwise) so I uninstalled it and downloaded an updated version, installed it (with the same license code) and since then it has seldom experienced the stalling. So I'm guessing it had something to do with the anti-virus. Perhaps it was due to the older version, but it had been running fine up until about a month ago. Hopefully the issue is rectified.
Thanks for the help. Love the geek police.