If the Westel 6100 modem/router is configured in bridge mode remember to power cycle it when switching the device connected to it.
Please show for the attempted wireless connection ...
Start, Run, CMD, OK to open a command prompt:
(For Vista or 7 type CMD in the Search box after Start)
Type the following command:
IPCONFIG /ALL
[Note that there is no space between the slash and ALL.]
Right click in the command window and choose Select All, then hit Enter.
Paste the results in a message here.
If necessary use a text file and removable media to copy the results to a computer with internet access.