Files and software that you don't use should be deleted. They might be the reason your PC isn't working properly. When your PC is fixed, instead of running like it's supposed to, it might be slowed down by the same files and programs. The point is that everything you don't use, delete it. If there is a point in the future where you need such software, you can always download it.
When you discuss the problems on the phone you can't be sure that your message was received by those who will actually fix your computer. This is why it is very important to talk to the person that will be working on it. You can do so when you take your computer there. However, the best way to do so is by writing all of the issues in a file that you will save on the desktop. Describe the issues in detail so that you can expect the best results. Then say that you have done so over the phone or in person. This way, you can be sure that no problems are going to be left out, and your PC repair will achieve the maximum success.