a different type of download percentage loss

[hg123]

I know some of the users have experienced losses in download percentages usually due to errornous data downloads. But today I had xolox slow right down as if it was about to stop dead so I closed it and was going to reboot my computer. But my cable modem's incoming and sending lights kept flashing really fast as if there was data transfer and my computer would not respond when I pressed windows start or anything else, like a desktop icon. My computer didn't freeze, I was still able to move my cursor. I had to reboot using the reboot button on my computer and when I started xolox again, my two downloads started again but with reduced percentages. One was about 70% but had gone down to 50% and another was about 45% but dropped down to 0%. I had this experience another time when xolox produced a fatal exception. Anyone else had this experience? ANyone know what may have caused the data to be lost?