I have a laptop running vista.  All my printers are gone, and I get a printer spooler eror at start up.  I can't install printers as well.  How do I repair the spooler?

Here you go.
http://support.microsoft.com/kb/324757

Try disconnecting the printer cable at both the printer and computer, then reconnect
making sure to connect fully. now reboot and see if the problem is solved.
A poor connection can cause this problem, however it can also be a bad cable.

There are also other things that can cause the problem as noted by others. On my computers it was the cables.