If your Windows Media Player is crashing and both SFC and SURT return no errors, I doubt that this is caused by corrupt system files :) Which programs aren't working exactly?
And the good procedure would be to get a Windows 7 x64 RTM and SP1 .iso, so you can use them with SFC to source clean copies of files, but that will only work if the corrupt files are from the RTM and SP1 version of Windows. Any files coming from updates (KBs), won't be present in these .iso.