flash.ocx is associated with the Adobe Flash player -- a pluggin. I have no idea why you need that to log in. This is a different issue. It would have to be repaired by reinstalling it:
To troubleshoot the blue screen we need to know what it says: error code and driver file if mentioned.
I can run a debugging utility on the dump files if you do this:
1 > create a new folder on the desktop and call it "dumpcheck" or whatever you like
2 > navigate to c:\windows\minidump and copy the last few minidump files to that folder. They are numbered by date.
3 > close the folder and right click on it and select "Send to (folder name).zip"
4 > use the "manage attachments" in the "advanced" reply window to upload that zip file here as an attachment.
This might point us to a 3rd party driver causing the error, if one exists for it.
Hey, why don't you just try a "System Restore" to a date when things worked. Start in Safe Mode if you have to:
Start > Run: msconfig
> launch System Restore.