Wireless connection drops constantly

can you paste your "lspci" result here?

Here is my lspci:
00:00.0 Host bridge: Intel Corporation Mobile PM965/GM965/GL960 Memory Controller Hub (rev 03)
00:01.0 PCI bridge: Intel Corporation Mobile PM965/GM965/GL960 PCI Express Root Port (rev 03)
00:1a.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Contoller #4 (rev 03)
00:1a.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #5 (rev 03)
00:1a.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #2 (rev 03)
00:1b.0 Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio Controller (rev 03)
00:1c.0 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 1 (rev 03)
00:1c.1 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 2 (rev 03)
00:1c.2 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 3 (rev 03)
00:1d.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #1 (rev 03)
00:1d.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #2 (rev 03)
00:1d.2 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #3 (rev 03)
00:1d.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #1 (rev 03)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev f3)
00:1f.0 ISA bridge: Intel Corporation 82801HEM (ICH8M) LPC Interface Controller (rev 03)
00:1f.1 IDE interface: Intel Corporation 82801HBM/HEM (ICH8M/ICH8M-E) IDE Controller (rev 03)
00:1f.2 SATA controller: Intel Corporation 82801HBM/HEM (ICH8M/ICH8M-E) SATA AHCI Controller (rev 03)
01:00.0 VGA compatible controller: nVidia Corporation GeForce 8400M G (rev a1)
02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 01)
05:00.0 Network controller: Intel Corporation PRO/Wireless 4965 AG or AGN Network Connection (rev 61)
End

I have the same problem. One moment I have connection, the other time I have no connection.

02:00.0 Network controller: Intel Corporation PRO/Wireless 4965 AG or AGN Network Connection (rev 61)
06:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 01)

I got the same problem on my HP 8510p laptop. And found the cure (as I think now)! Ubuntu 7.10 seems to use old version of the intel wireless firmware. All you need is:
- Download the firmware archive from http://www.intellinuxwireless.org/?p=iwlwifi&n=Downloads
- tar xvf iwlwifi-4965-ucode-what version you got.tgz
- Copy iwlwifi-4965.ucode from the unpacked folder into /lib/firmware/your kernel version/iwlwifi-4965.ucode and /lib/firmware/your kernel version/iwlwifi-4965-1.ucode (you should overwrite two files with the same data)

After that you need to reboot or just to say
rmmod iwl4965
modprobe iwl4965
Now on my computer it have been working for the whole night without any problem. But I can not guarantee it works everywhere.

I tried to change the ucode....now it "feels" better....but the connection drops now sometimes....but then all laptops and computers lose their connection to the AP...maybe there is a problem with my router????

I confirm this. Under heavy traffic, it disconnects in a matter of an hour. I find that disabling and enabling wireless networking in network manager "solves" this without having to reboot. I am now using the most recent firmware Anton suggested and it seems to be rock solid now. I'll be compiling a new snapshot of the iwlwifi driver anyway for good measure.

Please check this:
https://bugs.launchpad.net/ubuntu/+source/linux-ubuntu-modules-2.6.22/+bug/144621/comments/42
It completely solved my problem.

Hello. I'm having the same issue. My WiFi connection starts fine and typically stays connected for several hours. Then, for no apparent reason, I look connectivity and a reboot appears to be the only way to resolve it. I have a Sony FZ160E laptop and am using an integrated Intel Pro/Wireless 4965 WiFi card.

I've followed xpto_68's link and installed the package he referenced above:
https://bugs.launchpad.net/ubuntu/+source/linux-ubuntu-modules-2.6.22/+bug/144621/comments/42.

The instructions are a little sparse for someone new to Linux / Ubuntu, so hopefully I've installed it correctly. I'll report back if it doesn't resolve the problem.

Just wanted to follow-up to say that the instructions posted by xpto_68 (above) fixed my issue. Since following those instructions, my connection has not dropped once. Thanks for your help.

i am getting an error when trying to install the bug to fix my dropping internet connection