Why is my Windows 7 recovery folder 53% of my disk

This is not a standard Windows folder, so was created by some installed product.

Dell Backup and Recovery is often mentioned in that connection. So, if installed, better uninstall it first before continuing on. If you never installed it, then check your installed products in Control Panel > Programs and Features for a likely candidate.

Run an elevated Command Prompt (cmd) as administrator and enter the following commands:

c:
cd \
takeown /f "c:\system recovery" /r /d y >out.txt
icacls "c:\system recovery" /reset /T >out2.txt
rmdir /q /s "c:\system recovery"

This will delete the folder C:\System Recovery, but may cause to malfunction any product that uses it (if it wasn't uninstalled).

EDIT: Dell Backup and Recovery has now become SOFTTHINKS services.

Apparently this folder belongs to Dell Systems (not Windows!) and is used for it's own system recovery software see here

If you don't rely on Dell's system recovery (and use Windows system recovery or some other type of backup), most common solution is to remove (e.g. by uninstalling it though control panel -> uninstall a program, but there are several solutions) the recovery software, which will free up the space again.

I would strongly suggest to uninstall it, if it does not work at all, harrymc posted a possible solution on how to get rid of the System Recovery-Folder "more directly".