Boot the WIndows 7 DVD Repair console or Repair CD, click through to Recovery Tools list to run Startup Repair. It should offer to run System Restore if the System File checker doesn't first repair the files - it runs several dozen tests like this.
If not, choose System Restore from the Recovery Tools list and restore to before you randomly deleted the files. Let's hope these are files that SysRestore doesn't ignore in its operations.
If you need to reinstall, boot the Windows 7 install DVD, select Custom install, use drive tools to delete all partitions, create new ones as you wish, then format before installing Windows 7 to first partition. After install, newer drivers
will arrive via optional Windows Updates. Then any drivers missing in Device Manager can be found on the SUpport Downloads webpage for your model computer/device.