Sikpupi,
Going from Win98 to WinXP is a big jump. You are better off with a newer computer for running WinXP. (You do not want to have too many legacy components in a machine running WinXP.)
Do run the compatibility check from Windows to make sure your hardware and software will work with WinXP before you do the upgrade. (The things that are not expected to work are the Antivirus and the CD Burner software.)
Take Care,
Richard