With most laptops, a hard-drive swap is pretty easy - open the bottom hatch which covers the hard-drive, pull out old, insert new, close hatch - done in 10 min or less, and even the most unskilled person can accomplish this with minimum fuss within that time-frame. Hard drives are one of two things that are easy to replace in a laptop - memory being the other. Anything else involves a bit of technical know-how.
You will want a clean dust-free desk, and a small cup-like container to hold screws, and a small screwdriver.
And of course a replacement hard-drive, which can be acquired from any reputable computer shop, usually for very reasonable prices.
For those still worried, I have no doubt that a google search for "Dell <insert model # here> laptop hard drive swap" will come up with a bunch of text and video tutorials, which will tell you basically the same as above.
If one is still feeling anxious, the above computer shop can usually do the swap for you, often to include the backup. Industry standard is 1/2 hr labor time as a minimum, and that's all it should be, unless you go for the shop doing your backup as well.