Bit of an odd one this. One of our PCs is getting caught in a loop some time after being turned on, usually after a USB storage device has been attached - sometimes an iPod, sometimes a GPS.

Specifically, Windows Explorer starts showing a drive icon and letter (E:, as of right now) for the System partition (the small hidden one at the start of the boot drive). Then, the icon disappears. Then it reappears again. And disappears. It does this very quickly, at what looks like maybe 50 times a second.

CPU usage in this loop is also very high; averages about 66%. This machine has an i7 920 CPU, which is quad core with hyperthreading; so this usage rate works out to about 5 100% busy threads, along with whatever normal idle load is (particularly Task Manager itself).

Inspecting with Process Explorer shows that the device removal notification infrastructure has gone berserk. The threads in system service processes (i.e. apart from Windows Explorer) which are using all the CPU power relate to device notification. The Disk Management MMC snap-in also fails to run when the loop starts.

The only way to break the loop, it seems, is to reboot the machine.

Anyone seen anything similar to this, and know of a way to fix it?

Machine details:

• Windows 7 x64, fully patched
• i7 920, 12GB RAM
• Intel SSD 80GB (X25-M, I believe; not G2)
• 2TB 5.2K disk for bulk storage
• AMD HD 5870

Further hardware details await. I'm going to go through and update all drivers I can find.