What if the hard drive light keeps flashing?

Computer hard drive lights flashing non-stop, about a second flash, the desktop does not run the program, to Safe mode is the case, this may be caused by computer poisoning.

After the boot to wait a period of time, just after the boot it must be flashing non-stop, but if after a long time, or have been flashing, it is necessary to see if the hard disk is really read and write operations.

If the system does not have any operations, not in the update or create a restore point, there is no program to run (including anti-virus software), but always read and write the hard drive, it may be the computer poisoning.