Hey, dov...

This is a bit of a change of subject, but...
I just noticed something you mention in your post...
Pentium III 500...
If you are running Norton Internet Security and Norton A-V at the same time, you may run into some serious 'resource conflicts'. (Wondering how much RAM is being reported installed on your machine...)

It is possible that you will need to run only Internet Security with the A-V 'Auto-Protect' OFF...

Just think about your 'resources' when you have completed DownLoading a large file... The file will possibly be 'verified' and then 'hashed' while Norton A-V is scanning the file... All of this happening while there are maybe other files being D/Led and U/Led...
CPU 100% - Lockup - Crash...

This is not casual supposition on my part... I have seen this exact sequence occur many times.

It's not really any big deal to disable the A-V 'Auto-Protect', as long as you have Internet Security enabled and configured correctly.

I am in the process of writing about 'resource conflict' problems but it's a long post and not yet finished...
But, some quick coments for you now... Be sure to have a look at your settings for Paging Files (Virtual Memory)
The settings can vary so much it is crazy... Note what you have now, in case you wish to return to those settings, but, Please, try entering Maximum 768Mb and Minimum 384Mb... Then do a 'ShutDown' and normal 'Cold Start' (Not a 'warm-reboot' - Don't let Windoze, "do it for you.")
If you don't notice any 'improvement' in performance, leave the Minimum alone and increment the Maximum by 192Mb... If you get to 1,152Mb and still see no improvements, there are other problems...

On your Internet Security settings, it may be a good idea to delete all references to past settings pertaining to LimeWire and start over. The 'auto' function in Internet Security should be working whenever you add a new application, but there is certainly nothing wrong with checking all of this stuff manually !!!