Printers Disappear From Printer Folder

Recently I formatted my HDD, installed WinXP/Sp2, Office 2000 and AVG 7.0 Free Edition. After that, I noticed that (sometimes) all printers (including local ones) disappear. If I go to services (Administrative Tools) and stop Printer Spooler and start it again all the printers come back allowing me to print successfully. What?s happening?