I've been having issues with my clipboard on my Host OS and my VPC. Occasionally, it just decides that copy-paste is too complicated for my little mind to handle and so it unilaterally decides that it should no longer work. After a bit of digging and a lot of screaming, I found that I could get the clipboard working again by restarting the VM Additions service from the Services MMC in Administrative Tools. Hope this helps someone - and if anyone can tell my why my @ symbol and apostrophe still don't work..... :)