dell sent me a laptop preloaded with 7 pro oem. the oem disk package was sealed. can i use that oem disk to load on another dell pc or a non dell desktop?
Technically Yes (up to a point), Legally No.
The Dell OEM Windows disk will install and activate on pretty much any Dell hardware, however, you are only permitted to use it on the machine you bought it with as that is what the licence is tied to.
If you have other Dell machines that have lost the Media but are licensed for the same edition of Windows, there is no harm using it to restore.