Sounds like sd card is toast. PC recognize it? If so back up and reformat. If not recognized there are programs for repairing sd cards and partitiong and formatting. Be sure to format in default allocation size. Good luck
Did you check tv settings. perhaps unplugging tv reset some sort of hdmi port on off. Otherwise i would hold power button for 3 beeps and then for three beeps again. third beep will be double this time. Recovery mode should allow you to set system defaults. If that doesnt work you might have damaged hdmi out port. Keep us posted
Does your screen not unlock when you open KB? Usually opening keyboard will unlock the generic lock screen. If you have set a pattern or pin, didyou happen to choose a quick unlock key? My intercept gave choices of vol dwn, home, camera, or back buttons. holding the key you choose for 4 seconds will unlock your locked phone. Unfortunately you can also choose no emergency key. I can only suggest recovery mode if that doesn't work. Power on while holding menu, vol dwn, and end call buttons. Should boot to recovery mode where you can completely restore factory configuration. If you need your contacts or musicor other personal data then you MUST BACK UP FIRST.... There is a back up option in the menu.
The best way to improve performance similar to installing RAM would be to use a larger sd card. If your android phone is rooted you can go even further by partitioning your sd card and making a swap partition, which basically acts as RAM. Many ROMs require a swap partition to run the more resource intensive features of newer phones on older hardware like the intercept. Cleaning out unused data and restarting phone daily can also give you minor performance benefits.
Enable iphones bluetooth in discoverable mode. If you are using Windows 7, simply go to control panel and open Devices and Printers (under hardware if in category view). Click on add device. A window should appear with any available devices. iphone should appear here. If there is more than one iphone option choose access point. once you have paired your devices, probably via pin numbers, you should be tethered.