Utorrent's slowdown

[Snoopydog144]

I am having trouble with Utorrent. It began a week ago. What happens is that whenever I run the program, my download speed increases for maybe 20 seconds, then falls to near zero. If I haven't run Utorrent for a day, it can get up to 600kb/s for a few seconds. But then it starts to slow down. The speed drops and drops. 30 seconds later I will either not be downloading the torrent at all, or it's at 0.1kb/s or maybe 0.2kb/s. If I exit the program and re-run it right away, I am still at that 0.1kb/s speed. If I wait an hour, it will speed up to maybe 50kb/s for a few seconds before the speed drops again. If I wait a day, it will creep up to maybe 600kb/s, then drop again as I described. I thought maybe this was Comcast throttling me, but the Glastnost test says there is no evidence of throttling.

I've never had this trouble before. I am running Windows 8.1 on a new laptop. Utorrent is 3.3.2 build 30303. Newly installed. Can anyone tell me what to do or check? Thanks in advance...