I've seen Windows 2000 and XP pause when there is an application that is misbehaving. For example, iEx (a Mac Expose clone) would crash with the traditional error dialog box and I would close it. Right after, the machine would grind to a halt. I went to second a PC in my office and did a remote view of the processes running on my machine and found that iEx didn't actually close. I issued a remote kill and things returned to normal.
If you have an idea which application is causing the problem (ie: the Bluetooth), try running TASKLIST \\yourcomputer from another PC. You can use TASKKILL \\yourcomputer to terminate the process.
If you don't have XP on the second PC, visit
http://www.sysinternals.com/ and download the PSTOOL package. PSLIST and PSKILL will do the same things.