The Problem:-After installing a second hard disk in my computer as slave and it has started running slower.
Cause:-This happens if the drive is in PIO mode or,if the cabling is incorrect.
Open Control Panel>System
1Open Device Manager.
2.Double-click IDE ATA/ATAPI Controllers to display the list of controllers and channels.
3.Right-click the icon for the channel to which the device is connected, select Properties, and then click the Advanced Settings tab.
4.In the Current Transfer Mode drop-down box, select DMA if Available if the current setting is "PIO Only."
Also Check the cabling is correct (And a master drive should be on the end connector - any slave in the middle). Now in Device Manager, select the master controller - just above Primary Channel and Action; Uninstall. Then OK, reboot for PnP to try over.