Ok, I've downloaded the Windows driver from here: http://www.jazztel.com/archivos/descargas/ficheros/17052007085830Huawei%20HG520%20Wifi%20USB%20drivers.zip
I've unzip the file and click in Salix - System - Ndiswrapper Wireless Drivers. Then I've install the new driver (wlusb20.inf) and now I'm ...

Width Zydas I get this info:
iwlist wlan1 scan
Cell 02 - Address: E0:91:53:03:BE:5E
Channel:6
Frequency:2.437 GHz (Channel 6)
Quality=20/100 Signal level=20/100
Encryption key:off
ESSID:"WLAN_EE"
Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s
Bit Rates:6 Mb/s; 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s ...

Ok, this is dmesg | tail width WEP encryption on:
Registered led device: p54-phy0::rx
Registered led device: p54-phy0::radio
usb 2-1: is registered as 'phy0'
usbcore: registered new interface driver p54usb
ADDRCONF(NETDEV_UP): wlan0: link is not ready
ADDRCONF(NETDEV_UP): wlan0: link is not ready ...

@zAchAry : It's an emergency solution if your touchpad doesn't work. I've tried it on my Acer laptop and it works. Sometimes I have to repeat the last key sequence. I mean, Shift + Fn + NumLk twice.

@Terid: Yes, Xorg.conf.
More experiment:s
1. You have tried two usb mouse: a Microsoft Mouse and ...

I know this is not an elegant solution, but it can help you until you find another better. Unplug your usb mouse and type:

1. Fn + NumLk (check that you have the numeric lock light on)
2. Shift + Fn + NumLk

Now you can use numeric keypad to move the cursor and click.

http://support.dell.com ...

You can also try to disable the touchpad and see if usb mouse works ok.
Some experiments:

- Some laptops have a key for disable touchpad. For example, in an Acer you can use Fn + F7. Has your Dell a similar combination?
- Open a console (Alt + F2, write xterm, and try this command synclient ...

It's not a problem of Salix or GNU/Linux, Windows users have same problem width it. You can see a lot of examples:
http://en.community.dell.com/search/SearchResults.aspx?q=1525+touchpad

It's a defective design of Dell. Is it on warranty? If not, someone gives a technical solution:
http://en ...

A lot of problems with Dell 1525 touchpad:

http://ubuntuforums.org/archive/index.php/t-1068303.html
http://www.linlap.com/wiki/dell+inspiron+1525

In the second link someone give this solution:

I also have an Inspiron 1525. I use the Xubuntu 8.10 with Linux 2.6.28.3, the latest kernel.
I was ...

You both are right: if I turn off the WEP encryption:
iwlist wlan0 scan

Cell 02 - Address: E0:91:53:03:BE:5E
Channel:6
Frequency:2.437 GHz (Channel 6)
Quality=70/70 Signal level=-1 dBm
Encryption key:off
ESSID:"WLAN_EE"
Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s
Bit Rates:6 Mb/s; 9 Mb/s ...

Congratulations!
All of them look fantastic!