I hope i can help some of you out here who are experiencing right now with flashing red light and black screen. i just recently solved this problem today as i also experienced this red blinking LEDs and no display at all after i connected it to Desktop Manager doing the update. so here are the steps i did.
1. Try to pull out the battery and insert it again
2. If nothing happens, just leave the battery inserted with the red light blinking then press simultaneously on your key pad the ALT, SHIFT/aA button and DEL
3. If nothing happens again, then try to press again ALT, SHIFT/aA button and DEL twice in simultaneous motion (this is the HARD RESET for BB phone)
4. Pull out the battery after doing the reset
5. Connect your phone (without the battery) to your pc with the usb cable, wait until the red light appears again and for your pc to detect it.
6. Open your Desktop Manager, it will pop up an error message just press ok or retry.
7. Your device manager must detect your phone with a label of USB: Blackberry-0 (it will not show your phone's model for the mean time coz you did a hard reset)
8. On your Desktop Manager, you must see Device Connected (PIN): Blackberry-0, then go to Application Loader then Update Software.
9. During the Initialization of JV, you will be prompted to connect your device/phone although it is already connected, DO NOT REMOVE THE USB CABLE, just insert the battery then press retry.
10. Then you're done! it must continue load the necessary OS and files then wait for atleast 30 mins to finish the restore. you must see a loading bar with blackberry logo in your device after you inserted the battery and press the retry.
I hope this will help you guys. This is just my own method and i didnt even search the net for help. anyway im a techy lady and knows few tricks and just want to share it here. cheers!