Possible problem in Oracle/Vb.net application

We have an application Oracle as back-end with Vb.net as front-end is working fine since 1 year but before 1 week the application give me an error message "Cannot connect to database".

The both database and application available in same client machine - Windows xp

What the possible problem here ?

Why the application not connect the database ?
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slightwv (䄆 Netminder) Commented:
What changed?  Please don't say nothing.  Things that used to work do not just stop.  Something has changed.

Is there an Oracle error number?  They should start with ORA- and have a 5 digit number.

Did the XP Firewall settings change?  For grins, turn off the firewall and see if the problem continues.
egovernmentAuthor Commented:
Hi slightwv

I'm looking first time what the primary checking I should do.
slightwv (䄆 Netminder) Commented:
first thing is you need a better message form the application.  Did it produce an Oracle message?  Does it write log messages anywhere?

Did shutting down the firewall work?
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- does the database is up and running? the services is running? have you tested to connect to the database using sqlplus/any GUI tool?

- are you using odbc? check/test your odbc able to connect to the database.
egovernmentAuthor Commented:
This is oracle services is fine ?
egovernmentAuthor Commented:
Maybe the problem with


If I try to start it but it's not working but there no error message comming
slightwv (䄆 Netminder) Commented:

Well, you need a listener running.  If you do not have any others then yes, this is likely the issue.

From a command prompt post the results from:
lsnrctl start
egovernmentAuthor Commented:
I re-start the listener and re-configure the services

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egovernmentAuthor Commented:
My answer the correct
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