I had the same problem with xolox freezing up, using all the system resources. I installed it and could never get it to work.
I have a 300 Mhz and 64 MB RAM with Zonealarm - so low power PC.

I uninstalled xolox and reinstalled it in a separate partition of my
hard drive (luckily (or not) my hard drive recently crashed and I had to install a new one). In that partition I also put my MP3s etc - all files to be shared. So the partiton only has xolox and files to be shared. I started sharing limited numbers of files, and am incresing the number. Zonealarm is still active and I have been able to download music at over 200 kb/sec (cable). I think the secret is keeping xolox away from all other files on the hardrive that are not going to be shared.