• Scan external or internal HDD
• Recover data from HDD
• Fix Windows registry
• Scan the computer for viruses
• Scan the RAM for errors
• Browse the Internet. Yes, this is possible too.
• You can transfer the files from or to the external HDD connected to the USB port. (USB devices must be connected before UBCD4WIN starts)

For hard disk diagnostic, we recommend two tools which are available in ISO form. They can be burned straight to a CD after download is done.
The first is MHDD. This software application suits people who are already familiar with the command line interface and with DOS. This software application uses the command line to perform operations. Results are displayed graphically.
The second tool to diagnose hard disk is the Hitachi Drive Fitness Test.This tool performs diagnostics especially for Hitachi hard disks but it is also suitable for any other hard disk on the market. It works from a bootable CD. Just check here to find out how to get it and how to perform diagnostics with it.
There is actually another tool you could use for a system test-the Stress Linux. This is available on a bootable CD and it performs all system stress tests.
These were the free tools, and some paid computer diagnostic tools are also worth checking out. Some of these are highly reviewed, such as the SpinRite. This is a software application used to recover data from a faulty hard disk drive (HDD). It doesn’t just perform recovery, but it also performs hard disk diagnostic and will warn when there is a probability that the hard disk will fail.
The main features of SpinRiteare:-

• It operates on DOS/Windows
• It has a direct hardware level operation with hard disk controllers.
• It performs a super sensitive surface analysis and defect detection which is known as Flux Synthesis.
• It has the Dyna Stat feature, which is a data recovery technology that also performs deep statistical analysis.
• It is fast.
• It uses loss detection drive parameters.