Is there any free tool that can detect obsolete drivers, with a suggestion where to download fresher ones?
My laptop is a Dell E6400, but the Dell website is not very accurate when talking about drivers.
Try Driver Updater Pro.
Here is a review:
It's difficult to provide a centralized driver updater for Windows because competing device manufacturers are really the ones responsible for developing and releasing them. While the number of manufacturers of PC components is not as diverse as it has been in years past if you are buying OEM stuff (most of the onboard components are Intel-made these days), typically you are talking about a separate manufacturer for the chipset, graphics card (if discrete), possibly Ethernet controller, WLAN controller, audio controller (sometimes).
If you are using the Dell website (support.dell.com), try entering the service tag of your system rather than looking it up by model. Usually that narrows the list of drivers down further although I've had issues with some laptops wherein doing that still gives me 8 or 9 WLAN drivers instead of the one that is actually in the system. If you are having a problem with a specific device I'd say just go to the Del site, download the latest driver and install it. That way you know for sure you do in fact have the latest.
Windows Update (XP, Vista, 7) does provide driver updates, which you can use if your version of Windows is properly activated.