Downloads marketed as "keygen.exe" or "crack patches" frequently contain Trojan horses designed to steal browser passwords or encrypt your personal files.
Legacy software has no support from Sony or MAGIX (the current owners). Sony Vegas 7 Serial Number
If you already own a license for an older version, you can retrieve your serial number through official channels: MAGIX Account : Log into the MAGIX Service Center Downloads marketed as "keygen
Avoid risky workarounds
No legitimate company provides a “universal key” for Vegas 7. Avoid any site that promises one. Sony Vegas 7 Serial Number
To do this properly and ensure you receive a valid, transferable license: