I'll guess Windows If it were Mac, you would have an older Power PC system.
Update 7.0.1 is here: Adobe - Photoshop : For Windows : Adobe Photoshop 7.0.1 update
If that does not solve it:
Let's try a Prefs Reset:
Press and hold Control - Shift - Alt immediately upon cold-starting Photoshop. If you get the keys down quickly enough - and you have to be VERY quick - it will prompt you to confirm deletion of your established preferences, which will lead to them all being set to defaults.