The absolute simplest way is to contact Dell again and purchase a restore disc. If you are looking for a free way, however, do the following:
1) Locate your Service Tag (http://support.dell.com/support/topics/global.aspx/support/en/identifyyoursystem?c=us&cs=19&l=en&s=dhs).
2) Browse to Dell's driver page (http://support.dell.com/support/downloads/index.aspx?c=us&l=en&s=gen).
3) Enter your Service Tag and browse to your specific computer's driver page, then select "Windows Vista 32 bit" under Operating System.
You can download every driver if you wish, transfer it to a flash drive or burn to a disc, and install in the following order, rebooting after each installation:
1) Chipset - Intel Driver
2) Video (try Intel first, then nVidia, then ATI)
3) Audio - SIGMATEL
4) Network - Broadcom - Driver, then Dell - Driver for Bluetooth, then finally Intel - Driver.
However, the best way to reinstall drivers is to use the built in Windows Update technique. Only install your Chipset driver and the Broadcom driver. Then, open up your Windows Updates control panel and click the Check for Updates button. This will attempt to find all required hardware drivers, then you can install whatever is missing in your Device Manager (right click on Computer in the Start Menu, select Manage, click Continue of a box pops up, then select Device Manager on the left).