Hi Frank,
I to experienced these problems with SD, Ive been posting for a while on these forums now helping other users with issues and have come across many users experiencing the same issues, slow PC, slow browsing with IE, FF, BSOD's and so on... list goes on. However, I have just downloaded SD 5.0.0.174 and it seems to work without any of these problems. To see more info on 5.0.0.174, visit
http://www.pctools.com/forum/showthread.php?t=46290. I hope all goes well for you as well.
Best of luck
Chippa