Windows 7: regaining disk space

net stop wuauserv
ren %systemroot%\SoftwareDistribution SoftwareDistribution.old
net start wuauserv
rd /s/q %systemroot%\SoftwareDistribution.old

DISM.exe /online /Cleanup-Image /spsuperseded

bear in mind that above command is super-case-sensitive
sfc /scannow

Unfortunately in Windows 7 you cannot get rid off update packages in WINSXS folder (this can reach 12GB). You can clear it up in Windows 8.1 and later.