CS3 is officially not compatible with Win 7. You may need to try compatibility modes and experiment with your security settings/ user privileges.
Is there any way to install Adobe CS3 master collection, on windows 7??
I´m asking because a had the same problem instaling Adobe photoshop CS2 on windows /, and I contact Adobe Suport, and they told me to log in on my adobe ID, select Photoshop, and there was the software and serial to download. And it work fine.
While CS3 is not officially supported on Win 7 that is because they never tested it. CS3 was obsolete before Win 7 came out. Should work fine.
Try resetting preferences by starting PS and immediately holding down ctrl alt shift keys. IF fast enough will get a reset window.
Also make sure you video drivers are up to date.
If you have any 3rd party fonts or plugins disable them.