Hello darkluX
I see you've been busy, and I'm glad you read the link I provided, but I think we need to re-boot this entire thread. In your first post, you made no mention of dual booting between Win7x64 and an unnamed Linux OS. I had assumed that Win7x64 was the only OS on your machine, and offered advice based on that alone. In light of this new information, I think it would be wise to start all over again.
1.) The make and model of your machine. And specifically, does it support UEFI/EFI boot? Does it support both UEFI boot and Legacy boot in BIOS? (Some mfg's refer to Legacy boot as CSM Mode)
2.) Did your original Win7x64 installation (prior to installing Linux) boot using UEFI enabled in BIOS? Or did you use Legacy boot?
3.) Were you successfully booting Win7x64 and Linux prior to this problem? Or did it occur after you installed Linux and tried to boot for the first time? Or do you think that enabling boot time defrag using Defraggler is where your problems first appeared?
4.) Your situation now is: You cannot boot either Windows or Linux? Or you cannot boot Windows but can still boot Linux?
5.) Which Linux OS are you using? I ask because there are some that are 64 bit but do not work well with UEFI boot. (I found this was the case with Vector Linux for example.) Trying to install any of these could create the problems you're having.
6.) **Skip this-go to #7-I got ahead of myself here** You are aware of the difference between MBR and GPT partitioning, as well as how it relates to setting up the boot partition, correct? Here's an article to read that explains it far better than I can: http://rodsbooks.com...sk/booting.html Read every article you can find written by Rod Smith. He is one of the best references when dealing with UEFI boot and dual boot problems. http://www.rodsbooks...ders/index.html
7.) You mentioned trying the bootrec command, but I think there's more to using it than you describe. Try it again, but read this carefully before using: http://pcsupport.abo...ore-windows.htm
I'm sorry to hear that using Startup Repair didn't work out for you. I'm guessing that your priority is to get Windows up and running(#7), then attempt to get your Linux OS to boot as well(#6). The info from Rod Smith is a big help there.
Post back once you digest everything I threw at you and figure out some of the answers. Don't give up hope, at least not yet.