I am a customer advocate here at Dell headquarters in Texas. I'm glad to hear you found a way to fix the problem with Sonic. To be honest I'm not sure why it happened in the first place, as the installations are not supposed to effect each other unless they are installed together, and even then they usually are independent. As someone else posted, you can get the latest Dell drivers on the support site (http://support.dell.com). Personally, I would recommend using the latest Dell drivers and only going to the manufacturers version if something still doesn't work. The reason for this is that the drivers on the Dell website have been tested to ensure they don't cause other problems with the system. Using the manufacturers drivers should not cause a problem, however. While we had stopped shipping the OS and driver reinstallation CDs for a while, those disks were available from Tech Support if needed (and currently shipping systems have them by default again). If your system did not ship with an OS reinstallation CD I can most likely have one mailed out to you. If you need the CDs, or are just interested in having them "just in case" feel free to email me (customer_advocate@dell.com with 'ATTN: Larry' in the subject to ensure it gets to me) and I will see what I can do.
Larry Dell Customer Advocate