QUESTION On booting up my desktop PC I was greeted with the error message: 'NTLDR missing – press Ctrl, Alt, Del’. I followed the instruction and the message was repeated, so I reinstalled Windows XP. When I switched it on, there were no programs or files. In fact, all the programs remained on my machine, but the hard drives were listed with new letters and were inaccessible.

I use Acronis True Image 9.0 and an external hard drive for backup, but when I try to access the saved data Acronis reports: 'These are not Acronis files, or files are corrupted'. Help! Brian Hawley

HELPROOM ANSWER Reinstalling Windows wipes (formats) your hard drive, deleting all your files and programs and leaving you with a fresh copy of the operating system. This process has also rearranged your hard drives, labelling them in a logical order. Windows has kept all your files intact, but you’ll need to change the security permissions to access them.

Click Start, Control Panel, Folder Options, View, then clear the option to ‘Use simple file sharing (recommended)’. Click Ok.

Now locate your ‘original’ Documents and Settings folder. This should contain all your old files, such as photos and documents. Right-click it and select Properties, Security (click Ok if a warning appears).

Click Advanced, then Owners. In the name list, select your current user account. Tick the box marked ‘Replace owner on sub-container and objects’ and click Ok.

This will grant your user account the permissions it requires to access the contents within. Repeat these steps for any further folders you need to access.

For your Acronis images, run a disk check on the external drive. Plug it into your PC, then right-click it in Windows Explorer and choose Properties, Tools, Error-checking, Check Now. Ensure both boxes are ticked and click Start. Allow Windows to fix any problems it finds.

You should also apply any updates to Acronis – especially if the backups were created using a newer version of Acronis. Visit for more updates.

See also: How to fix everything: the ultimate guide to fixing technology

Free tech support in the Helproom Forum