Laptops have low powered usb ports so you need extra power to power a hard drive or cdrom.  I bought a slim cdrom drive from colordrives that came with a extra connector that connects to the mouse/keyboard port, and it works with laptos using this extra power source.  I also bought a ide usb adpapter which came with a separate 120volt adater.  It worked fine with my laptops using this power adapter.  This ide usb adapter is ubiquitous on ebay.  However, it comes with no case/enlosure and  the power supply went out on me after a few days of use.  I contacted colordrives about it and he directed to send it back with ebay item number.  I paid to send it out to him weeks ago and I have yet to hear from him.  I would expect a similar experience by buing it from a different ebay seller.  These adapters sell for about $15.  I have several drives thatI would like to use with my bare bones(<$100) laptops, but I am afraid to invest in anymore of those adapters.  I also bought a slim 2.5 -9mm usb hard drive enclosure kit from colordrives.  It works fine with my desktop, but wont spin even with the extra usb connector on my laptop with two usb ports.