Running out of disk space (winsxs, installer, system32, SysWOW64 directories)

Hello, 

I have a windows server 2008 r2 standard SP1 x64 virtual machine with only 821MB of free space available out of a 35GB single hard drive.

After scanning the hard drive with TreeSize I see the following folders taking up the most space:

Windows\winsxs = 15.7GB

Windows\Installer = 2.6GB

Windows\System32 = 2.4GB

Windows\assembly = 1.4GB

Windows\SysWOW64 = 1GB

Program Files\pagefile.sys = 3.1GB

Program Files\ProgramData = 1GB

Is there anything that I can safely remove from any of these directories...especially the "winsxs" directory?  Or do I need to increase the size of the hard drive (I would prefer not to if at all possible).

Thank you!