in my Windows 7 pc, i upgraded office 2007 in to 2010. now when i'm sending emails it's going to save in the outbox but mail is get sent.  

Hi,

Which type of email account are you using? IMAP, POP3 or Exchange?

Is there another copy of the outgoing emails in the Sent Items folder?

Please first make sure if you have the "Save copies of sent items in Sent Items folder" options enabled. Go to File > Options > Mail, scroll down to the "Save messages" section, select the check box before "Save copies of sent items in Sent Items folder".

In addition, does this issue happen to all outgoing emails or just a certain type of emails? Such as a replying message? If this issue only happen to replying messages, please also have a look at the following KB article and check if it applies:

http://support.microsoft.com/en-us/kb/293031

Please let me know the result.

Regards,

Steve Fan
TechNet Community Support

No, still the same... my problem is when you send a mail the email is going to the destination. but it's not showing in my sent items. when i'm checking those mails are in outbox.( i created a .pst file and use the default as that .pst path.) not in the offline. email always online.

Hi

Go to File-->Account settings-->Account settings and check if there should be 2 e-mail accounts. If there is, delete the one that does not have the check mark.