The best I can offer, then, is to troubleshoot this with you, which will take you through a lot of different things to find the problem. If you decide you don't want to go through all the things, just let me know. Otherwise, I'll try to keep working with you until we get this figured out.
A couple more things I need to know to help with figuring this out...
1) How are you doing the xdcc send command? Are you typing it as /msg <nick> xdcc send #? or are you opening a query window (private message window) and just typing xdcc send #??
2) When this happens with fservs, is it when you type the trigger, or when you use the GET command on the fserv itself?
First things to try out...
1) Type /remote off (or /remotes off... I forget if there is an "s" and I'm not at home right now to look) and try.
2) Open Task Manager (Ctrl-Alt-Del) and list out everything you see on the processes tab for me. To save time, you may want to just take screenshots of the processes tab. If you're writing them out, I just need the process (image) name... not the rest of the information listed.
3) Get Ad-Aware and Hijackthis from the web (use google to find them). Run those and paste in the results here (don't fix anything unless you really know what you're doing... some things shouldn't be fixed that those find). Those aren't really IRC issues, but may be associated for some reason, so it's worth trying. If nothing else, it might get rid of other unwanted stuff that Norton will not find. I'd also say to get Spybot Search & Destroy, but that is no longer free. There may be a demo version or something out there if you want to look. Just let me know which program the info is from when you paste this info or screenshot it.
4) When you freeze, do you get any message from the server stating trying to send the file on *** port? Do you get any messages in the status window at all?
5) When you freeze, press Ctrl-Break and see if it stops the freeze and keeps you connected. If it does, let me know if the file starts or not.
We'll continue from there after you paste the results from these.