After you issue the command(s) below, the next time SQL starts, tempdb will be sized accordingly.

Split the 2GB into equal parts, for however many tempdb data files you have.

For this example, I'll assume you have 2 data files -- if not, adjust accordingly.

ALTER DATABASE tempdb

MODIFY FILE ( NAME = tempdev, SIZE = 1GB )

ALTER DATABASE tempdb

MODIFY FILE ( NAME = tempdev2, SIZE = 1GB )

ALTER DATABASE tempdb

MODIFY FILE ( NAME = templog, SIZE = 512MB ) --<< or whatever values matches your max expected usage