No, we are not talking about a furry critter stashing away bits of cheese on your brand spanking new machine, although a laptop mouse problem can definitely be just as annoying. Unfortunately this is a fairly common problem when you use a PS/2 mouse, regardless of whether you are running a new operating system or an older one.
The most common sign that there is something amiss is odd and unpredictable behavior when the PS/2 mouse is plugged in and in use. Windows and folders may open up at random for instance, or the start menu may open. More alarmingly, the laptop mouse problem sometimes persists even after you remove the mouse and revert back to using the touch pad. In such cases, only a reboot will get everything working the way it was, which is of course a bit challenging with everything opening up onscreen. And plugging the PS/2 mouse back in after a reboot is likely to cause the same laptop mouse problem.
Interestingly enough, everything seems to work as normal if the PS/2 mouse is attached after Windows has loaded. Some users have tried to solve the laptop mouse problem by removing and then reinstalling the PS/2 drivers or checking the msconfig file for programs that may be causing the odd behavior but to no avail. This causes many users to suspect that the PS/2 port may be damaged.
Your next course of action at this point is to hook up the PS/2 mouse to a USB port by way of an adapter. This may be all you need to do if the laptop uses an older operating system. You could also check for an IRQ conflict when the laptop is booted up with the mouse connected to the PS/2 port. If there is a conflict, you could resolve this by setting certain interrupts to ‘reserved’ in your BIOS. Some systems may also have an internal input device that can be disabled in BIOS. This may just be a simple yet effective solution to your laptop mouse problem.