The bad thing about Recent Documents History is that Windows XP has to calculate what should be put there each time you boot Windows, which can slow things down.
1. Open the Registry Editor (select Start/Run, type regedit, and click OK).
2. Navigate to HKEY_CURRENT_USER\Software\Mcft\Windows\ CurrentVersion\Policies\Explorer.
3. Create a NoRecentDocsHistory D_WORD key. Double-click the value to open it once it is created.
4. Set the Data Value to 1 to enable the restriction.
5. Click OK and close the Registry Editor. You'll need to restart the computer for the change to take effect.
" Windows XP Tips: Disabling Recent Documents History "
Reference : techpraveen.com