x301 super slow boot up even after clean OS re-installation

[Procter]

My X301 boots up really really slow (up to 10 min) now. I tried clean install of win 7 pro 64bit but right after I started to install other software (think advantage stuff, office, firefox etc) it got back to the slow status. Symptom is, it hangs for about 5min at windows start up page, and after I key in password, it hangs for another 5-10min until desktop shows up and mouse can move.

Checked a few threads, and someone advised that it was the CMOS battery. Looked up maintenance manual and I believe the "backup battery" is the cmos battery. But I could not find the battery size. For desktop PC, they just use a li-ion button battery on mb, but this one is wrapped the wired out.

Where can I get the battery? THX

[Tasurinchi]

Before opening up the TP and swapping the battery, I would try to boot with a Linux distro and see if it also takes so long...

My 2 cents...