If it is a Retail copy, Full or Upgrade, you can reinstall it on that laptop, as long as the license key you use is not used on any other computer.
You can also do a Clean install of Win 7 with either a Full or Upgrade version. You can also reinstall it even if it was a System Builders OEM version as long as it was originally installed only on that system.
There is NO restriction for reinstalling Win 7 with any version on the same computer it was originally installed on.
Not sure why theog said that if it was an upgrade version you couldn't reinstall it.