|Yousaf, There's a script you can download at the link below.This will increase the timeout to 19 seconds. Scroll down to line 81(left column) and click on "Increase Slide Show Timeout" to download a vbs file and save it to your hard drive (you may want to right click and use Save Target As). Double|
click the vbs file. You will be prompted when the script is done.
NOTE: If your anti-virus software warns you of a "malicious" script, this is normal if you have "Script Safe" or similar technology enabled. These scripts are not malicious, but they do make changes to the System Registry.
If you're comfortable with editing the registry read Reply #2 in the thread at the link below.