howard coleman

thanks in advance for some info... in order to speed up my computer i recently decided to upgrade to WIN XP (home version) from my WIN 98 second edition. i called and ordered the upgrade from Gateway. during the initial stages of the upgrade i was asked to insert my WIN 98 disc. after looking everywhere i am unable to locate it. according to Gateway i will need to purchase the XP install rather than the upgrade since i lack the 98 disc. my daughter has a WIN 98 S E disc. would it work if i used her disc? i don't want problems w Microsoft down the road but do feel that i purchased my WIN 98 and one is enough. she has only one disc. is that all there was to WIN 98? i would like to zero my hard drive before installing XP so as to start w a clean computer as i was told by a Gateway tech that it may be slowed by accumulated undetectable programs. does that sound likely and is zeroing the proper solution? i really would appreciate any advice. howard coleman