You can always put the disk back in and run the bootable CD diags (link is in my previous post) and/or continue pursuing the Windows misconfiguration.
ok guys, so yesterday i was really frustrated and went my guts and bought a new HDD and inserted, formatted and installed a fresh windows and then all my drivers. and guess what, the prblem is gone and my computer feels 20X faster.
what still bothers me though and from the numbers and tests i couldnt pinpoint the exact issue for sure.
anyway thank you all for your help and input's. really appreciate it.
Alternatively if you have the means, using an adapter (2.5" to SATA) you can connect that disk to another computer as an auxillary drive and run a full battery of tests (bootable CD HDD diags or Windows based utilities).
You shouldn't be bothered by not determining the root cause because when you did the full install of Windows to a new HDD you effectively performed two solutions at once, consequently neither the hardware (failing HDD) or software (OS or other) can be pinpointed.