Photoshop CS2 on Vista Home Premium

[Chrispy]

This is not a problem I'm having myself, but it's something my friend is having. Unfortunately he might be too shy to post himself.

(See attachment.)

Anyways my friend has Photoshop CS2 and has this big problem whenever he opens it up. The whole computer lags out and the colour depth looks like 256 colours instead of something like 32 million. When we close the program, everything goes back to normal including the colours.

I thought maybe it was a RAM/memory issue, but then again every other application works just fine - including ImageReady, which comes with Creative Suite. We've tried reinstalling, uninstall/delete everything/reinstall, Googling, and even changing the memory cache preferences in Photoshop itself.

My friend's comp is Vista Home Premium, DX10, GeForce 8400GS, 1GB RAM, with dual core processor. I haven't done anything like update his drivers or anything, and while it could be driver compatibility issue, I just want to see what you guys think first (plus it's not my computer so I'm a bit hesitant ), if you reckon it could be something else.

What do you guys think?

Edit: Forgot to tell ya, he did not have this problem with Photoshop at first (it used to work fine) - he reckons something has changed which made it this way.