It can probably be done, but you need to theoretically...
1. Reboot in XP and install MSN WM 7.5.
2. Reboot in 98/98SE/ME and install MSN WM 7.0.
3. Compare files from 7.5 with 7.0.
4. Copy over newer files from 7.5 onto 7.0 folders.
5. Test to see if it works.
Make sure you backup replaced files in case newer ones don't work.
MSN WM download links:
http://www.mdgx.com/add.htm#WMI'm not going to create scripts for an automated install, because I don't use [MSN] Messenger, and don't have enough time for testing.
But if you or anybody else like to do this, please post scripts/results here, so we can all benefit.
Thanks.
Hope this helps.