Wireless Signal Loss

I have new Acer Aspire 5739G laptop and fresh Windows 7 on it.

The wireless card is Intel WiFi Link 5100.

The problem is that wireless works only in short distance with access point - max distance is about 5 meters.

In that distance everything works fine.

But if I go farther or to another room it disconnects.

With other laptops all works fine even on very large distance.

I tried such things (nothing helped):
* uninstall, reinstall or update drivers
* install newest drivers from Acer site
* install newest drivers from Intel site
* tested with xp & vista drivers
* on network connection properties unchecked all things except tcp/ip v4 protocol (microsoft networking,sharing, link layer topology,QoS, TCP/IP v6 ..)
* disabled homegroup
* on adapter properties changed signal frequencies (1,6,11),
* on adapter properties changed standard type to work with: 802.11 b or g
* on adapter properties changed signal to MAX, don't use power saving
* disabled Internet security, firewall
* Changed access point signal broadcasting with no encryption or wpa
* it disconnects from another access point the same way (problem with system not wifi AP)

Maybe something forgot to say, but there was few hours of testing and can't fix it .