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#11
Official Windows 7 SP1 ISO from Digital River « My Digital Life
download the right version there, burn it and boot from it on sick machine
If the PC is from your company, and they own it, then I would suggest you use extreme caution when attempting any repair. Many companies use custom installs and attempting to overwrite the existing installation could be even more problematic. You should have some means of contacting the support team that provided you the unit and contacting them would be the more practical solution.
HTH