hi
I'm so tired of this, and really unhappy. I hope anyone can tell me what to do to solve my problem. Or maybe only what causes it.

Whenever I have quite large documents open the slightest thing I do causes ps to destroy my image.
Example:

Here I was working on an image sized 7680px x 5000 px, several layers, total 197mb. In this example after applying an 8.7 gaussian blur to one of the layers the corruption occured. When I hit ctrl-z the corruption dissapeared but when I applied the blur again the corruption appeared again, only on differnt places in the image.
The blocks you can see are located in the different channels, eg in my red channel this corruption comes in on differnt places then in the green channel.
It sometimes does happen that I see this type of pixel corruption on one zoomlevel but it disapears when I zoom in or out. Once I save the file the state of the corrupt pixels becomes permanent.
It's not only after a gaussian blur this happens. It could be a brush stroke, a transformation or any randomly choosen action...
Sometimes it even happens on a differnt layer then I was working on. Or in a layermask. I'm getting paranoid, constantly zooming in and out to check my images. saving my files over again and again with different names so that I can easily com back to a not corrupted version. not funny.

I'm working on a pentium 4 2600, with only 512mb, win xp, cs3. In the past I used ps cs on this same machine, on that configuration as far as I know this corruption never occured. But then I didn't chop as large images as I do now.
Could it be the ammount of ram?? (the ram itself is good, tested it several times) Strange it doesn't happen on files with smaller dimensions but lots more layers, which filesize is evenly big or even bigger then for example mentioned one.

Can anyone explain what happens and what I shoud do?
Thanks!

Does this happen on smaller images? If not then I'd be willing to bet it's a RAM problem. I'd up the RAM and/or shut down any unneeded processes running in the background.

Thanks Tofu,
I already shutdown unneeded processes.
It didn't happen on a file that exceeded 260 mb, with almost 300 layers (vector, and pixels and adjustments) and a load of extra channels, with a dimension of approximately 1200 x 1600px. I think that is about the maximum pixel dimension my pc can handle at the moment.
The corruption did happen to files with smaller filesize though (eg 100mb) but bigger dimensions, over 2000 px sqaured or bigger.

Maybe an upgrade (read: pc replacement) should do the trick, but I can't afford that at the moment.

I'd still upgrade your RAM. Max out what the system can take. Heck I don't even recommend running XP alone with less than 512MB of RAM. Running a resource-loving program like CS3 on top of that? Yeah max out the RAM. If maxing the RAM would be more expensive than a new system (as is my case at home) then you'll have to budget for that new PC or a Mac.

Right, thought of that, and tried it. But this pc is really having it's own habits and is very selfish:
One day I came home with an extra 512 mb, after installing though windows didn't boot. Bios was fine, but as soon as it was xp's turn I got this message saying something like windwos can't boot cause file such and such can't be found. ( Can't quite rembember what file).
Still with the extra ram installed I tried to boot linux from a live cd, it ran like a charm. After de-installing the extra ram windows would boot up fine as if nothing ever happened.
I tried both modules in different slots as soon as I had them both installed, windows wouldn't boot. I've asked several 'experts' about it they al were puzzled.
So it leaves me with either a replecemant or the Gimp, I guess.

sounds like a hard disk problem, most likely bad sectors. Backup your harddisk, run chkdsk /f /r. It will have to run at boot time after restart to access the system areas Windows locks when in use. If you get any bad sectors reported, clone your HD to a new one a.s.a.p.

Your PS problems may be related to bad sectors on the drive it uses for a scratch disk. Get a second HD to use for the Windows swap file and the PS temp files.

Though you make me worry, still lots of thanks vokaris!
Alreaddy added another, separate, scratchdisk in the past, but I think I didn't disable a partition on the systemdrive for that purpose.
I'm gonna have a look at that. And tonight I'm going to run chkdsk.
How can I change windows swap?

run chkdsk /f /r on all your drives. Get a good disk defragmenter. I've been using PerfectDisk and very happy with it.

Changing windows swap file (virtual memory):
- right-click My Computer - Properties (or Control Panel - System)
- go to the Advanced tab - Performance (visual effects, etc, etc) click on Settings
- go to the Advance tab, at the bottom see Virtual Memory, click on Settings
- you'll see a list of drives and VM spaces allocated for each one. By default you'll have C: System Managed File.
- Select C:, click on the No Paging File radio button, then Set
- Select D: (or whatever drive letter you have for the temp files), select system managed size (or type in your own numbers in MBs, typically 1.5 to 3 times the size of RAM), click Set

Click all the OK buttons to close the dialogs. The computer will restart for the changes to get into effect.

lol Tofu, I see, I just need another lcp installed.
Thanks voks for your hints, I'm going to do the chkdsk thing now. See what it comes up with.