Symptoms of a dying HD, please

Macbook Pro 13 mid 2010, OS Lion 10.7.5] at least 30 GB free space, memory to the max, acting strangely.
Create movie file, cannot see it. Invisible. Restart and it's there. More spinning beach balls

Have you run disk utility and done a repair permissions and repair disk??

Could be the Hard drive is going out but try running disk utility first. If you have Onyx running that on automation would not hurt.

Also you could run the hardware test on it to see what it says:

Using Apple Hardware Test - Apple Support

Lisa

At least 30 GB free... and what size is the OS X partition?

While it could be a dying drive - If that's the free space on anything larger than a 100-200 GB partition, you flat out don't have enough free space and what free space you do have is fragmented from one end of the drive to the other with not enough contiguous free space for the operating system to use adequately and you are using the slowest portion of the drive.

To expand further, if you are seeing the machine just be slow, as in it's taking 10, 15, 30 seconds - possibly even a minute to do things that use to take 1-2 seconds - you need to free up more space on the drive - particularly for creating movie files.

If you've been running that computer since 2010 and it's never had a clean install or been defragged - it's highly unlikely that you have contiguous free space larger than 100-250 MB any where on that drive. Meaning just about any movie is going to have to be written all over the place.

On the other hand, if you are seeing your boot time, application launch times, right click menu pop up, etc. in the 2, 3, 5, 7+ minute range - in my mind - you have a dying drive.

Memory to the max take it as 16GB on the 13" 2010 model?

Also on that 30GB free space, your model can have up to a 500GB hard drive. Great on a 100/200 drive as bobtomay suggests, but on a 250/500 drive it is simply too full and choking. Aim is to have 25% free space so OS X can work anywhere near efficiently.