ora-01034 : oracle not available

[sap]

when i want to connect to oracle database with each & every username/password that are provided by default,an error messege is flashed "ora-01034 : oracle not available" this problem is not faced each & every time.
also at that time it is not possible to connect to database through active server pages as same error is seen in browser.
system details:-
oracle version 8.1.5(server)
platform : windows 2000 professional
machine : pentium iii 866mhz
ram :128mb
h.d. : 20gb
i am connecting through asp using oracle ole 0040

 

[sem]

Oracle is not available while being down due to some administrative needs or due to system crash for AFAIK 8.1.5 is not certified for W2K. There is nothing wrong with your passwords/connection. Contact your DBA.