How many computers can I link my iPhone to?
By design the iPhone can only Sync to One iTunes Library at a time...
SYNCING with iTunes
See here > http://support.apple.com/kb/HT1386
From Here > http://www.apple.com/support/iphone/syncing/
Thanks but I have had problems with my computer and have had to reinstall windows twice and when I download iTunes and sync my iPhone it says I can only sync with another 1 computer can I reset it?
Take a look at this page on "How-to Geek":
Because of what you've done, your phone sees your computer as a "new" computer. Just follow the directions here:
Retrieving data ...