why does my computer loose my printers .

While using win 98 all prints like it should but when I try to print in excel the printers disappear and I have to reboot to get the printers back. I believe it is a spool 32 issue but am unsure how to correct the issue. After I reboot the printer will print again for a while and then I loose it again and have to rebopot again. I am on a network and use only windows 98 operating systems. I use office 97 word and excel.