I just got my arduino uno in the mail today with a kit that i bought (Arduino starter kit | bol.com) but when I connect my arduino to my computer, the serial port doesn't show up. I have tried reinstalling the drivers which hasn't worked, i have tried connecting it to a different computer, which hasn't worked. My arduino has the atmega328p chip. Thanks in advance!
Which operating system are you using?
Have you tried a different USB cable?
It is the one that has the ch340g chip? If it's true then you need this driver
https://cdn.instructables.com/ORIG/FTM/QNA3/I84BBUNS/FTMQNA3I84BBUNS.zip
As long as you were sold a legitimate arduino (and by the looks of the site i am almost certain it is) then you have a high probability of getting things to work. Try a different cord, but also, make certain to test a different usb port. Some ports aren't always true ports, and will only supply power. If neither of those work, open devices or device manager (assuming you are using windows) and look for any unspecified devices, or a device that disappears when you unplug the board. From their you can try and update driver software. If all else fails the website you used has 30 day guarantee so you could return it.
Cub:
(assuming you are using windows)
That's why I askked which OS 
assuming that your board is a clone, you will need to install a driver for the ch340 chip, this chip converts the usb to serial that the Atmega328p will understand.
this is the link for the ch340 driver:
https://sparks.gogo.co.nz/ch340.html
Hi guys, maybe this can help, i just fix the problem with pc not recognizing the arduino board. I have windows 7 64 and hav the same problem with the arduino so i made a lot of work thru the wb sites etc
I just got rid of the carpet of proteous Labcenter electronics in the Program files section (not the program files x86) and that`s it! my arduino got installed and working.
Healthy. Open the control panel. Then the device manager. Above the port should be an unknown device. Open the device by clicking. Click search for the driver. He will think about where to install. Give Arduino and let that go. Good luck.