windows 7 - Win7 cannot sleep because of GRUB

I have Win7 on an MBR HDD for 6 years now, that was my primary operation system, but I intend to use Linux instead.

At least I am trying out several Linux distros on another HDD, which I set to GPT from Windows.

That HDD is sda, so by booting first the GRUB menu starts, and I can select Windows 7 booting from sdb if I want.

After a while I noticed that I cannot put Windows 7 in sleep mode, it logs out, but nothing happens after that. I am not sure whether this had been the situation in the beginning (1.5 months ago) of this multi boot experiment or I got this "feature" later.

I checked the sda and noticed that I have 2 small partitions. One is unknown with msftres flag, and one is the fat32 I created for GPT booting. I got a screenshot from that:

I am pretty sure I wanted to have only a single ~250MB FAT32 partition for GPT booting, but the installer created 2 partitions. I pressed the back button, because I forgot to add the biosgrub type (and I read somewhere that it is needed for GPT booting) and I made this screenshot then. I think I did not notice that I have 2 partitions, not a single FAT32, because I was concentrating on taking screenshots.

Now my question is that is there a chance, that these 2 partitions cause that Windows is not capable of sleeping? If not, what can possibly cause this kind of problem?

Edit:

I attached the BIOS power management settings:

As far as I understand S3 should be enough, so the problem is not there.

I removed every pendrive, so USB devices does not cause the issue. Sleeping worked for 6 years with the current mouse, keyboard, monitor and UPS, so their USB connections are not the cause.

I checked with GRUB Win7 loader and BIOS F12 direct boot. The problem occurs only with GRUB. So the following statement of Christian Isaksson

No, partition layout and/or GRUB has nothing to do with Windows sleep mode.

is not true.