ios 5 restore/backup problem

Upgraded to ios5 on my iphone 4.

After that I tried several times to restore my backup and it is not getting restored

so I lost all my contacts, calendar, evrything except my Apps.

So I backed up my new data ( on windows 7 system as well as on icloud ) and then again tried to restore ( from computer and icloud )

but it can't be restored.

Any solutions...