when i connect my vb.net coding with sql server server not work

hi,
actully i know i m asking silly question but it is my problem,when i write coding in vb.net abt update or delete data it shows msg but sql server not updated or delete my data.why it is happen.i saw my coding many time and also my crystal reports are not making after run msg show connection failed.i m really very upset coz it is my project work.plz some one help me.
with warms regards.