Follow these steps in NT to change the spool directory.
Occasionally, you may notice that your print server may hang when logging onto or stopping and restarting the spooler service. This occurs because of an overly large number of documents in the spool folder.
If the buffers of your printers can hold them, you can send documents faster by implementing an LPR fix. If not, or if you aren't using TCP/IP Printing, then copy the files out of the spool folder to another location on the hard drive, and copy them back a few at a time.
To free up space on your system hard drive, you may want to change the default location of the spool folder on your system. Moving it from the Spool\Printers folder of your System32 location will do the trick.
You can change the spooling folder for all printers or for individual printers with a change to the registry.
For all printers:
"DefaultSpoolDirectory"="<Full path to new spool>"
For individual printers:
"SpoolDirectory"="<Full path to new spool>"
Note: Editing the registry is risky, so be sure you have a verified backup before saving any changes.