Computer running slow and programmes not responding

Please could someone help
My computer doesnt seem to be operating properly.
When I click on any links to web pages on emails the computer freezes and is imobile for about 1 minute.
Also on lots of sites my computer freezes when I click on certain links for about 1 minute then returns.
I also get a lot of programmes freezing and getting the message not responding

Hope someone can help

It could be a virus, trojan spyware or malware. Try and do thorough checks in safe mode.

Here is a good post to read:

Read This First - IMPORTANT Instructions

Also:

Check your Event Viewer via Administrative Tools.

Open the System as well as Application tabs and look for red X errors that coincide with your problem. Details here:

How to view and manage event logs in Event Viewer in Windows XP

Basic information on Event Viewer errors can be found here: EventID.Net