It also has Eraser E only. I've explored every dropdown menu etc. and there is no Eraser without an E. If CS5 has information from an image, that may be the problem. I had scans of 2 1948 newspaper articles. I put them together about a week ago and annotated them on my iMac. I found better copies had been made a few years ago, so I tried to erase the annotations and correct them. There was no eraser I could use to enable me to select my background and erase. I moved them to my MacBookPro and found no eraser there. As I use CS5 all the time, I'd surely have noticed it.
Are you able to access CS5 on a Mac?
I have 104 GB of pictures on one Mac. I use only Photoshop and know what I am talking about.
On March 31, 2016, I was able to add the correction to the annotation on the attached picture.
As the picture will show, the black eraser track is its apparent former size but the drop-down window does not show the drop-down menu for this eraser.
Nothing in any book describes how I have successfully used Photoshop these many years. Neither is there anything online.