I have uninstalled, and reinstalled and rebooted to no avail.
Are Photoshop and OS fully updated and have you performed the usual trouble-shooting routines (trashing prefs by keeping command-alt-shift/ctrl-alt-shift pressed while starting Photoshop, 3rd party plug-ins deactivation, system maintenance, font validation, etc.)?
"Are Photoshop and OS fully updated.."
Not ph shop because it can't be opened, OS - yes
" and have you performed the usual trouble-shooting routines (trashing prefs by keeping command-alt-shift/ctrl-alt-shift pressed while starting Photoshop, just tried that - no luck 3rd party plug-ins deactivation, can't deactivate beacus can't open ph shop.
system maintenance, I think that is pretty much done font validation, don't know what that is - surely can't be something like that ??)
Looking thru Program files found version 5.0 that wont' open either. Remember, the old versions have been sitting in there for some years with 7.0 working fine. A second PC here has 7.0 on it and it stopped working as well - same behaviour. We have a older PC here as well we hardly use (XP pro as well), it has 7.0 on it which works fine(!!).
What have you changed on you computer? New hardware, new software? Something is now causing a conflict.
Go into Help file of OS and type in Event Log. Load and look in Application tab. Look for Error entires. Click on it if you see one.
You want to look for Faulting Module which will give you a clue as to where problem is.
If all else fails buy Photoshop Elements latest editon. Probably has more features than what you have, and will work on modern computers.