hi,I upgraded to windows 8 following the recent £25 pro upgrade offer from win 7 and all was running fine. however, last night and the night before i am experiencing some strange things and i'm not sure if it's hardware or software. i believe it's software. what's happening is when i switch the pc on, i get to the log in screen and type the password but it goes round in a loop, i press enter and get a black screen then it returns me to the log in screen. do it several times and unless i reboot, it doesn;t move forward. after this, logs in fine but my internet connection stops and starts all the time. i know its not my internet as my laptops all work fine. my pc is connected by a solwise 1gig homeplug. it was all working fine but the last 2 days have been a pain. especially when i'm trying to study online. my system is: core i5 3570k at 4.2 ghz khuler 620 cpu cooler gigabyte Z77x ud5h mobo F14 bios 16 gig of hyper x 1600 mhz ram 120 gig ocz agility SSD 2 tb back up drive 1.5 and 3 1tb back up drives. blu ray disc fractal design r3 case coolermaster 500 wt silent pro PSU modular. windows fully updated. avg 2013 AV cisco network magic pro office 2010 etc. any thoughts? re-install win 7 again? re-install win 8?