Hiren’s BootCD is pretty legendary, and anyone who’s ever worked in support or systems administration has probably used it at least once (or has several version of it lying around still.) The rescue disc is aimed squarely at repairing Windows systems, and includes a wealth of tools to that effect, including antivirus tools to scan your hard drive, anti-malware utilities to clean out spyware and adware, even rootkit detection tools. Hiren’s BootCD can also help you repair, adjust, or re-flash your system’s BIOS or wipe your CMOS, clean out temporary files and folders, securely erase files, back up your data to another hard drive or to the network, update and back up hardware drivers, scan your system for hardware failures, repair lost or damaged partitions, and much much more. We’re only scratching the surface here. It’s completely free and always has been. Even if there are other tools in your toolkit, Hiren’s BootCD should be among them.
The Trinity Rescue Kit is a customized Linux distribution that’s designed specifically for troubleshooting and reviving ailing systems, whether you’re running Windows or Linux. It fits nicely on a CD (or a USB stick if you prefer) and once booted gives you tools to reset lost Windows passwords, scan hard drives for viruses and malware, clone drives, recover lost partitions, even open up the drives as network shares so you can get files off of them and to other computers on your network. It’s completely free, although a donation to the developer behind it is always appreciated and keeps the project alive.