Any Mac user.

[joshdell4765]

I'm using a MacBook pro and I accidentally installed el capitan again on to my computer. After it booted up to the install process it stared to install it gave me a circle with a slash, is my old files still on there and is there any way to go back to my main boot.

[itsmeee]

Not sure what you mean by you installed it again.  You may have overwritten your previous install in which case the answer is maybe...  Your best bet is to pop in some installation software and launch 'Disk Utility' and perform 'Repair Disk' as well as 'Repair Disk Permissions' on your boot drive.  That might get it working, I believe that is due to any number of file issues.  It has been 3 years since I owned a mac though.  

 

Also can you give a little more explanation of what you were doing?  It may or may not be helpful.  Definitely wouldn't hurt though

[TDP_Equinox]

A little more of an explanation would be helpful, but if it is what it sounds like it is, if you boot holding option and choose your boot drive, you should go back into Yosemite (Or whatever OS you had before)