I have been told that if you have Norton Anti Virus installed using 'System Restore' causes problems.
I would say as a blanket statement, that is false. I haven't run Norton since 2003, but when I did use it System Restore worked fine.
Norton doesn't agree with some systems, especially Norton Internet Security that includes a firewall and other security tools so something may have changed, but if everyone had a problem with System Restore because of Norton I think we would have heard about it.
I agree that SR will not likely help with your problem, although it won't hurt. Try doing basic maintenance as already suggested first. Before you download anything, use what is available on XP. Do the basic maintenance that consists of:
Error checking (Check Disk, that will examine your hard drive for problems)
Do those in the order listed. All these tools can be accessed form your hard drive's properties:
Click My Computer, right click your hard drive's icon and select Properties. Disk Cleanup will be under the General tab and while you're there you can see how much space you have on your hard drive. If it's almost full that could explain your problem and the clean up should free up some of that space when done.
Then do an Error Check and lastly a defragmentation that are found on the Tools tab of the hard drive's properties.
If that doesn't help, you may need to check for spyware/malware as already suggested. See this tutorial:http://www.bleepingcomputer.com/forums/Und...lers-tut41.html
If you feel you need to use HijackThis for some stubborn malware, or just for a check up (which I recommend), see this tutorial:How to submit a Hijackthis Log
Otherwise it is hard to tell what the problem might be from your description. Are you saying that this slowness only happens when you click on the My Documents icon in your Start Menu? What about opening programs or other folders? Did this happen suddenly or come on gradually? The more details you can give the better we can help you.