I am using Flash CS5 and am running into the same issues on 2 different computers. Both are running Windows7, 16mb RAM, plenty of speed and health. The Flash file is very simple, and only has 3 layers and 20 keyframes. Nothing out of the ordinary.The problems are as follows:

1. when selecting an item on stage to manually move it, I move it, but the image appears to stay in it's place. However, if I scroll the stage up or down so the stage disappears than reappears, the image is located where I wanted it. Keep in mind, all layers are unlocked.

2. If I go in and retype new text, the update is not showing, again, unless I scroll the stage so as the text moves off screen and back again, then the updated text is there.

3. After making changes to the file, the "save" under "file" is grayed out, when normally it is clickable. It appears to the system that no changes have been made, yet there were changes made.

4. After making said changes, and I go to "save as", saving the file, then reopening it, it reverts back to the older file, with all of my changes gone.

5. Working with the timeline, has similar issues. Adding a keyframe or tween or AS, it does not appear in the timeline unless I click out of it and back into it. Even then though, it doesn't stay, even after saving the file.

6. Selecting a keyframe with an object on the stage, is not selecting that object. Typically, al you normally have to do is select that keyframe, and the object appears with a bounding box on stage, yet this is acting strange as well.

The other thing that is weird, is that it progressively got worse as time went on through out the day. Didn't have any issues at the start of the project, it just slowly then quickly started acting up.