Vijay,

I have had experience running 24x7 NT boxes and they normally do not require regular reboots.

Are you able to check the Task Manager before you reboot?
This may help you isolate the problem.

You may find that it is the same process causing the problem each time, prehaps the print function within the application needs to be looked at or the other option may be to apply the latest Oracle certified NT service pack.

Hope this helps.
John