They do. But expect them to charge you for the 1 minute task. It's a simple task of plugging the RAM into the memory slots of your motherboard, and closing back the casing. If you can do it yourself, why not save the money?
If they're nice or you're their frequent customer, maybe they'll close one eye and waive the charge.
For hard drive corruption, maybe they'll just replace it with a new drive. High chance some hardware fault in the HDD and a simple format won't fix it. If you request them to help recover or migrate data from old hard disk to new one, maybe separate charge. Again, price of the new hard disk and installation charge apply.