That's VERY odd. I don't think I've ever heard of anything like this before. I suppose it could be malware, but the symptom of just one momentary freeze - both in normal and safe modes - doesn't sound like any malware I'm aware of. And while the fact that it happens in safe mode would tend to indicate a hardware problem - again, the fact that it happens only once for a minute and then everything is fine is VERY odd. But, let's do some checking:
Please boot to the recovery console and run chkdsk /r
. If you can't get to the recovery console, open a command window as administrator, type: chkdsk /r
, press ENTER, and when asked if you want to run it at the next boot say yes. Then reboot. Be sure to use the "/r" switch.
To check the ram, download memtest (http://memtest.org/
). Burn it to a cd using a dedicated .iso burning utility (http://www.petri.co.il/how_to_write_iso_files_to_cd.htm
), make sure the cd drive is at the top of the boot order in bios, then boot to the newly created cd and run the utility.