Right click the C drive in Windows Explorer, go to Properties, then Tools and click on the Check Now button to check the volume for errors. Check the box for Automatically fix file system errors and then click the Start button. It will tell you the check will be done the next time you reboot your machine, say OK, close all open windows and reboot your machine.
When your machine reboots the Disk Check will take a while, maybe up to 15 minutes or so. Please post back telling if that made a difference or not. There are other things to try.
I have a Gateway computer that has Windows XP. I have purchased antivirus software and have downloaded and the software tells me that there are no viruses and I have analyzed and defragmented, cleaned out cookies etc. I also have high speed internet that I have thru my local telephone company. My computer continues to run very very slow. Everytime I go to even move my mouse I get error messages saying (not responding) Please help I just don;t have the finances to go out and purchase another computer at this time. also my computer is apprx. 4 or 5 yrs. old.