I installed a 3 months giveaway "bit defender total security 2013" in my "windows 7"
N just few days back i upgraded my windows to "windows 8", everythng worked just fine
But today only 2 days of my giveaway license were left, so I downgraded to "bitdefender internet security 2013" by inserting a key in "total 2013", it told me that it is a "internet security key" and advised me to downgrade, and so i did
Took some time, then at the end of process, it said 'restart the computer to complete the i stallation'
I clicked on "restart now"
My laptop did shutdown as usually but upon power up it is showing a message
"Your PC needs to be repaired
The operating system couldn't be loaded because a critical system driver is missing or contains errors.
File: \windows\system32\drivers\bdelam.sys
Error code: 0x000000f"
Please help me out, solving this cause my laptop won't start now
P.S. I do not have windows installation media, but i have Ubuntu in a pen drive, if it helps