Spooler server halts

Hi all.

I have a strange and imprevedible problem with the spooler service: an
old windows nt 4.0 svr with sp6a high encryption (PDC) now acts only as
print server; sometimes the spooler service stops and must be
re-started; the event viewer doesn't show problems.

I didn't find similar problem searching on inet.

Any suggestions?

TIA

Steve