I ahve tried connecting my Epic to my computer via the USB cable however my computer is not recognizing the phone and I cannot access the phone via the my computer screen which lists all connected devices (except my epic)
I've fixed that problem by unchecking USB Debugging. Try unplugging your phone and then uncheck it. (Home/Menu/Settings/Applications/Development/USB Debuggin)
Try a different cable. I've helped at least 3 different customers with this exact problem with an Epic and after we swapped out the cable it worked- and they were using the included USB cable. (all this is assuming it's not really caused by a defect in your phone or micro SD card)
Also try this:
Go to the phone and dial ##8778#
Make sure the top option UART is set to Modem and the bottom option USB is set to PDA.
In the service and repair stores the phones are set with other settings to connect to the diagnostic systems. Sometimes it doesn't get reset to where they need to be on accident.
Do you have the Samsung drivers installed for your PC? If not, please go to http://downloadcenter.samsung.com/content/SW/201009/20100901010102890/Samsung_Mobile_Driver_V1.3.800... and install the drivers. Also make sure USB DEBUGGING is ENABLED by Home/Menu/Settings/Applications/Development/USB Debuggin. Windows does not have the drivers for the Epic, and these must be installed to be able to see your Epic from your PC.