if Win98 has been installed in ur system, u can get key by doing this:-
1]Go to Start>Run, and here type regedit and press Enter.
2]Then expand the HKEY_LOCAL_MACHINE branch, by clicking the + sign before it.
3]Here similary expand the Software branch.
4]In Software, Navigate to Microsoft branch.
5]Expand Microsoft branch by clicking + sign.
6]Here inside Microsoft branch, navigate to Windows branch.
7]Expand Windows branch and Click on the entry named CurrentVersion ( do not expand CurrentVersion by clicking on + sign ), now in the Right Side Pane, look for the value Product Key, this is ur serial key....
Note down it and close Registry Editor....
if u dont have Win98 on ur system, contact technical support....