You don't have to format, helfit, but it is advisable. If you have the upgrade XP CD you will be asked for your Win 98 CD during the installation to prove you're entitled to the clean install.
Huawei P10 review
1995-2015: How technology has changed the world in 20 years
How VR is being used to simulate space
New iPad, iPhone SE & Red iPhone 7 on sale now
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.