Member Rara Avis
Probably nothing, Karilea.
The only problem with freeware/shareware programs is that they tend to fall a little behind the bleeding edge. Assuming you downloaded the latest WS_FTP release, I'm guessing the developers just haven't tested it well enough with XP yet. If you DON'T have the latest version, 7.5, that would be the first thing you should try. They "claim" it works with XP …
Here's one possible "trick" to try. After you close WS_FTP, open up the Task Manager and see if it is still running. Chances are it still is, which is what is locking up your system. If you see it, click on it, then click on the Close button. And wait patiently, because it may take a little while. (In older Win systems, you could get to Task Manager with Ctrl-Alt-Delete, in older NT systems, you could right click on the Task Bar, but I think in Win2000 and probably XP you'll have to find it in the Start Menu under Programs/Accessories/System Tools. TM essentially shows you all the "processes" currently running.)
Finally, if those don't work (or are too much trouble), you can always try another FTP client program. With any luck, Chris or Sharon will stop by and tell us what they are running under XP.
Here's a link to a TON of freeware/shareware FTP tools. You'll find the link to WS_FTP 7.5 there if that's the route you want to take. The only other one listed that I've used is CuteFTP and it wasn't bad at all. Or, wait for Chris or Sharon to make an entrance …