I arrived at work this morning to see some updates were available for WinXP. I have SP2 installed and my system has been running fine with no problems. After the updates were installed my computer needed to be reset.

When it tried to boot back up no operating system was detected. I put in my WinXP disk to try and repair the problem. I got to the partition management option only to see my 200gb drive had been reduced to a mere 131gb.

I checked the BIOS but the correct capacity was being displayed there.

I tried using some Partition Magic rescue disks to redo my partitions. Once again the correct drive capacity was being displayed. I set my partitions and formated the drive in NTFS.

When i returned to WinXP setup's partition management options the partitions i had just set were still present showing the full 200gb capacity but i tried moving on to the format options setup was unable to continue and the 131gb limit was displayed once again.

At this time a delivery man showed up with a brand spanking new 160gb drive which i promtly installed. When i tried to install windows the new drive was also showing a 131gb limit (an identical 131069mb limit to the 200gb drive).

Until i installed the Windows Update my system was reading all hard drives correctly. I have reset the CMOS but it made no difference.

I have run out of things to try...

Look for 48-bit LBA support. This option is hidden somewhere since XP-SP1, a Google should help you further.

Hi and thanks for your reply

I have had a search on google and MS Knowledge Base but i can only find solutions that involve editing the registry for pre-SP1 installations. I am running WinXP SP2 and from what i can see on the knowledge base, the registry entry that is suggested is ignored in the SP2 version of windows xp.

I did try the hotfix that was available for download but it did not solve the problem.

I am getting my problem before windows is even installed and i do not have the option of editing the registry at that stage of the installation.

Are there any drivers for those big harddisks? Go to one of the Read: posts up top, and see if one of the manufacturers have a test-utility for your brand HD.

W2K: http://support.microsoft.com/default.aspx?scid=kb;en-us;305098
XP : http://support.microsoft.com/default.aspx?scid=kb;en-us;303013
http://voyager.adsl.dk/docs/large_drives.html
In Google search: 48-Bit LBA Support for ATAPI Disk Drives in Windows

See if there is a BIOS-update available. Other than that, I'm afraid I am out of options. Someone else please?