Why is my USB mouse disconnecting and reconnecting randomly and often?

"From what you describe, nothing immediately comes to mind what the cause of the issue you are observing might be.

A few things to keep in mind:

The longer it takes to reproduce the failure, the longer it'll take to debug unless you are lucky. Your best bet is to try to find a way to reproduce the failure as quickly as possible.
You can count on experience and a consistent method of debugging (i.e. the ""shotgun"" debugging approach rarely produces the expected results -- not that I'm saying that is what you are using).

Typically, I would start with a minimum system setup to rule out the variables (1 CPU, 1 CPU Fan, 1 DIMM, 1 Video Card, 1 Hard Drive, 1 Power Supply, etc.). It is best if you have all ""known good"" components. Then, try to rule out subsystems. Unfortunately, at home you likely have limited tools and resources, so you have to improvise smartly.

Rule out the OS/drivers (easy if you have spare CD's & hard drives):

Does this happen when you run the system from a Linux boot CD?
Does this happen with any other OS installed?
Does this happen with a clean install of your current OS?

Rule out the keyboard and mouse:

Do your keyboard and mouse/mice always work on a another system?

Rule out the motherboard power rails:

Does the 5V rail at the USB slots stay near 5V or does it dip (a meter may tell you this, but an oscilloscope can give you a better idea if the power rail dips)?
What does the 5V rail look like on the PCI USB card?

This answer might now solve your problem, but hopefully it'll move you towards finding the cause of the issue."

"If it happens with several mice and several USB interfaces, that leaves software. Are you using the Windows default HID driver for mice? You might try installing the latest software from Microsoft: http://www.microsoft.com/hardware/windows7/support.mspx

This is a regular USB mouse, not a wireless one, right?

How does it behave after a clean boot?
http://support.microsoft.com/kb/929135"

"Had similar problem for a year on Windows 10 with my Logitech G102.
Reinstalling driver would not help. And changing ports would help for 10-60 minutes. But here what I noticed, I have two HID-complaint mouse entries in Device Manager:

If I remove one of them in a short time it will reinstall itself.
So instead I disabled it (Right Click → Disable device).
Note that for me it worked only when I disabled top one.
Its been two weeks and no disconnects yet!"

"Look at the Windows event logs to see if there is any indication of a service/driver failure.
Look at the motherboard settings for integrated peripherals.
Check the setting for USB on chip support. The manual is not clear on the meaning, however, I did have a system that when legacy (1.1 & 2) was enabled, USB devices would disconnect.

From the manual I cant tell for sure what the setting on this motherboard means. If you disable on chip the keyboard and mouse are forced to enabled (according to manual) this would seem to imply the enabled setting allows access to other USB devices outside of windows (like boot from USB)."