The wireless card on my computer (or my sister's I don't know) became insane, it's signal is disappearing and appearing at random and it's really irritating, wtf can be causing this?
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Hmm my cards operate on the 2.4 ghz band, I think it might be interference from someone else's microwave

How do I fix that?

Yes but nobody was using the telephone here

Yea, I'll second the telephone theory, maybe a neighbor though?  I have the same problem with my card, it'll drop the signal whenever the phone rings.  Luckily the phone rarely ever rings.

I've been wondering the same thing, which is why I don't understand why more devices don't allow power users to adjust the frequency to account for such problems.

IIRC, the channel doesn't change the frequency it broadcasts on, because no matter what channel I set mine on, it still goes crazy when the phone rings.  I could very well be wrong though, and it is just my phone kills everything.

IIRC, the channel doesn't change the frequency it broadcasts on, because no matter what channel I set mine on, it still goes crazy when the phone rings.  I could very well be wrong though, and it is just my phone kills everything.

Actually the frequency changes, but very little (2.412 GHz [channel ][/channel] to 2.477 GHz [channel ][/channel]).

The key is to find the channel with the least interference, usually 1, 6, or 11. Maybe even try netstumbler to see if there are any other networks closeby broadcasting, then use a channel that they aren't. Also you can try to repoint it's antenna, and the antenna on the router to get maximum signal strength so interference doesn't affect it as bad.

I'm currently using channel 6.  It doesn't really matter though right now, because I am back at my apartment at college now, and I don't have the problem here luckily.

You can set the channel that routers broadcast on, which leads me to believe this actually isn't the cause of MY problem. Why you can't adjust the frequency of a wireless card, especially since wireless cards came after 2.4GHz phones (right?) they couldn't see this as possibly being a problem? Stupid.

Phones, of all the goddamn things. Phones.

It is because to change the frequencies at which it works you'd need to change the shape/size/length/thickness of the antennas because they have specific resonant frequencies

All of my computers work on the 2.4gz band.... and there are five cell phones in my house. Between me and the router there is a microwave.... and although it does interfere, I have since upgraded the antennae for the router and placed a cheap repeater in this room (that also helps the connection with the other computer on this side of the house). It solved all of my problems.