Linksys WMP11 Problems

Where is your router or access point compared with where your computer is located? How far apart are they? Any obstructions between them (walls, floors, filing cabinets, etc)? Is either near a microwave oven or a 2.4GHz wireless phone?

All of my questions were directed at interference and/or obstructions.

Since you seem reluctant or unable to answer, what signal strength to you see at your computer? Is it steady, or does it come and go (the signal, not your connection)?

Microwaves and wireless phones have been known to cause interference.

Walls and other physical obstructions (cabinets, bookcases, etc.) will weaken the signal, as will distance.

Can your computer "see" any other wireless networks (even if the signal is weak)? If so, are they on the same channel as your uncle's? If they are on the same channel or a "close" channel (e.g. he is on channel 1 and the other one you see is on channel 4), that also can cause interference.

Are the 6 computers that do not have problems located near yours, or are they in a more favorable location (closer, fewer walls between them and the rounter, etc.)?

Since you don't know what the physical setup of your uncles router is, does that mean you are poaching his signal? If not, then maybe you should ask him where the router is and what is between it and your computer.