Windows Repair is a portable tool which can help you get a damaged PC working again, useful if for example you've just removed a stubborn malware infection and now your system is seriously misbehaving.
The program's tabbed interface first walks you through some basic recovery steps. There are pointers to some free antivirus tools, for instance, and buttons to check your hard drive for errors, run the System File Checker, and create or restore a System Restore point.
For the real power here, though, click Start Repairs, select "Custom Mode" and click Start. And here you'll see options to reset Registry and File permissions, re-register system files, remove system policies commonly set by malware, and repair WMI, your firewall, IE, Hosts file, Winsock and DNS cache, and more. Just check the boxes next to the repair you'd like to carry out, click Start and Windows Repair will fix the selected problems for you.
There's no doubt that Windows Repair includes some powerful options which may be able to help you fix all kinds of odd Windows issues.
However, this tool can also cause plenty of problems of its own. So choosing to "Repair Winsock", for instance, might get your internet connection working, but could also break some low-level network-related application, such as a firewall. Reinstalling these programs should get them running again, but it's still best to be cautious: apply the Windows Repair tweaks one at a time, and only when you're completely sure they're necessary.