WIRELESS LASER MOUSE 6000 v2.0 RED LIGHT ON TOP OF MOUSE KEEPS BLINKING

SOURCE: Microsoft Natural Wireless Laser Mouse 6000 doesn't work

Hi
If you take the batteries out there is a screw in there. unscrew and open (not easy) with flat knife in the edges wiggling.
attach and touch all the inside wires. I have had the same problem and it is an internal connector problem. Opening and closing aint easy and will take a little patience but it will work.
Good luck

SOURCE: microsoft wireless laser keyboard 6000 v2 - keys suddenly stopped/not working

i had the same problem, i checked the batteries with a DMM and the measured 1.4v i replaced the batteries with new and i still had the same problem. anyway i ended up taking the keyboard apart and found where the antenna is connected to a push on type connector alongside the pcb board inside the keyboard, the connection was slightly corroded. i cleaned it up and it is working fine know, even with the old batteries.

SOURCE: microsoft Wireless Laser keyboard 6000 v2.0

Try going to Control Panel, then click on keyboard and Keyboard Properties will come up. Then click on Key Settings and then click on Restore Defaults. Hopefully that will do it. Had a similar problem with an MS 4000 KB.

SOURCE: why does not microsoft wireless mouse laser 6000 work suddenly?

Well, I had the same problem, too, and I just turned my PC off, waited a few seconds and turned it on again. This means I really turned it off completely; normal restarting didn't work. Maybe that helps you too. 

SOURCE: Microsoft Wireless Laser Mouse 6000 v2.0 x key stuck

This seems to be a "systemic" fault with this product.

Throw it away, buy a replacement and forget Microsoft!