all the time. In a Win98 and XP scenario, the first install would be the 98(which you already have), the second would be XP on the second drive. Note that you will need to format the XP install in FAT32 if you wish 98 to be able to see and use the XP portion. Here's more reading>>>

http://support.microsoft.com/default.aspx?scid=kb;en-us;306559&sd=tech