Noticed recently that my PC was hanging on the Gigabyte splash screen for a long time during boot up. Normally gone in a flash. Have two sticks of 4MB RAM tried boot up with each on their own in turn. No improvement and memory diagnostic ok. Reset cmos (battery out and shorted pins) and loaded defaults. No Change. Then noticed an HDD dissapeared from the list, normally 2 WD HDD's and 2 SSD's and DVD. Checked connections ok. Swapped affected HHD with DVD (what a mistake to make) and now neither the DVD nor the HDD listed Doh! Measured output of plugs open cct 12v and 5v supply ok but lack access to an oscilloscope now to check for AC ripple/spikes which may have damaged devices first the HDD and then the DVD? Now boots at good speed without hanging with HDD and DVD disconnected but USB Mouse not working even in the cmos screens. Tried a another port but no dice. Looked through settings in cmos but cant identify anything that may be set wrong on default setup to prevent USB mouse working. Mouse is a TeckNet x8900. (Anker software) PSU is an Arctic 700. Mobo GA- Z77-DS3H rev1.1. CPU i7-3770K GPU GTX980Ti Hybrid Am i missing something in the CMOS setup and/or has my PSU turned rogue? Could a virus affect detection of devices? Need my mouse for my gaming fix. Strangely the keyboard also USB works fine.