Everytime I update my iphone on the laptop, the thing crashes and the iphone needs restoring – although I then have to go on the desktop to do the restore as it doesn't seem to work on the laptop – also when syncing it can sometimes just hang and not do anything with the result i cancel it half way through………….I'm sick to the f^&*(&^*( back teeth of this – anyone else have similar problems?

Confused. Are you trying to sync it against two different iTunes libraries?

http://www.mobilecomputermag.co.uk/20080121261/how-to-sync-an-iphone-with-two-different-pcs.html

Delete the downloaded update on your laptop, which will force itunes to download it again.

It's in C:\documents and settings\<user>\Application Data\Apple Computer\iTunes\iPhone Software Updates