"i want to install windows98 on my pc alongwith xp mainly because i want to use excel its pretty good with many features than spreadsheet in xp sp2"
Excel is nothing to do with Windows 98 or Windows XP SP2.
Win 98 and XP SP2 are operating systems.
Excel comes as part of the Microsoft Office package - a completely different product.
Assuming you have Office, you can use it with Win 98 or Win XP - although why you want to install Win 98 along with XP is beyond me.