Start By Eliminating Unnecessary Startup Programs & Services
The more programs you have running in the background, the more that need to close when you shut down the computer. Conflicts between the various programs will frequently prevent the computer from shutting down as you'd like.. Personally, I use ALL of the cleanup steps in the link below to clean up the machine which allows it to startup quicker, run a little smoother, and remove unneeded junk.
It appears like you may have some items that are bogging down the computer.. First, if you haven't already, take the case off the computer and use compressed air to blow out all the dust and junk from around the heat sink, processor, power supply, and all fans in the machine.. Get rid of the junk.
Next, please follow the procedures below to cleanup the machine:
First, uninstall unneeded programs from the Control Panel/Add-Remove Programs section..
Next, make sure you have no spyware which is slowing things down. Please download, install, update, then run the free spyware removal program from the link below:
SUPERAntispyware Removal Tool
Next, follow ALL of the steps in the instructions below. Shut down unnecessary start up programs and services, PLUS delete all the junk files from the computer. It may take a while to perform all the procedures, but it will help the machine run, shutdown, and boot quicker:
For Windows 2000/XP, ignore the first couple of sentences about checking "resources" and the "Performance tab in the link below but follow the rest of the procedures including the "Services" links at the bottom.
How To Shut Down Unnecessary Start Up Programs
Now clean out the junk files:
How To Clean Unwanted Files From The Hard Drive
After following all the procedures above, run Error Checking/Chkdsk and Defrag to optimize the hard drive:
How To Run 'Error Checking/Chkdsk' On Win2000/XP
Hope this helps.