Mac Pro 1 1 OSX 10.7.5 suddenly malfunctioning everywhere

I need help and am at a loss. I have a Mac Pro 1 1 running osx 10.7.5. 2 x 2.66 dual core Xeon with 16gb RAM. Suddenly today acrobat kept crashing and would not work anymore. SHortly after my dock would not auto hide / show. I had to click near the dock area to show it and when it did pop up the genie effect and animated icons when opening did not work. Any menu's I went to had no hover ability. I had to click or click and hold to get from a menu to its sub menu. Now left clicking suddenly sticks and drags a selection, I can't move a window and let go, it just sticks, and at times I have to double or triple click something to make it work like a link or opening an app. Also, when something won't click and I click a few times a menu pops up with any open apps and it cycles through the apps. I did a clean reinstall of lion and tried a number of things but have no clue what there is left to do.

Also, about a week ago it would not start up. It could not find the boot disk. I fixed that but it seems like snce then everything has gone downhill. Is my mac dying or can it be saved?