my usb wireless intellimouse explorer (microsoft) frequently doesn't react anymore; sometimes for a short part of a second (but many times in a row), sometimes for several seconds. i tried to change the place of the receiver already a lot of times, but nothing helped.

Take it back, get a new one.

When this happens to me I change the batteries and all is OK.

Click on the activation button on the transmitter and wait 2 minutes. If that doesnt work change chanal. If that doenst work then maybe the bateries you use are not suported by MS. Rechargebles dotn work well in the Explorer mouse. Energizer and Duracell have been good with me. Energier are the best with it and MS recomands it.

I too have a MS wireless optical mouse that goes out to lunch sometimes. Changing to new batteries did not help. Sometimes it would go out several times per day, sometimes it would work OK for a month. reloading the mouse driver did not help. Pushing the button on the transmitter and then pushing the tiny button on the bottom of the mouse (use a pencil point) seems to almost always get it working again. It seems to fail more often if the speaker is between the transmitter and mouse. Moving the transmitter seemed to make it better. Consider taking it back like the first response said in you have no luck.