@essebebe thanks for taking time to find out and reply. I think your ref 1. giving this link
How to change your password for broadband access points rightly to my modem.
For your ref 2. there is only one difference i.e., MTU instead of MRU.
For ref 3. I will surely try to implement it. But for
D-Link DSL502T the default network settings worked very well.
Update: USB connection now works in Kubuntu Linux. And so does the internet. But no LAN connection is detected with MT882 LAN port plugged to PC in Linux.
For ref 4. the guide says UT Star 304R2U is compatible with Ethernet port only. But my modem is compatible with USB port too, in fact only USB is working.
In short my LAN goes off whenever I start XP with the MT882 attached through LAN cable - Network Cable Unplugged; have to set NIC configuration to 10Mbps/Full Duplex. In Vista it works. In Linux (Kubuntu) it doesn't. I don't know how to configure LAN NIC to use 10Mbps, will read your ref.
@superprash2003 actually I installed another XP on the Same Machine just to check whether there are any conflicts of the ethernet drivers with other software in my Older (working) XP. So now I have 2 XPs, Vista and Kubuntu. After correcting the Vista boot menu Newer XP startup gives hal.dll error - have to correct it. Others work well. Thanks.
@rahul_7860 Thanks. Good to hear that someone else has the same modem and it works well. But mine doesn't. Actually as you can see from this and the earlier posts my LAN is not working with this modem. I will PM you.