yeah you can delete the account - by it not having a "users" folder means it was never logged on to.
it seems like someone on your computer ran a program, which created the user and the program would have secretly emailed some hacker the ip address, username and password. since your firewall doesn't apparently allow remote desktop, the account couldn't be logged into
i have seen similiar incidents where a foreign username was actively logged onto a remote desktop session, running a denial of service attack against some website. they logged in, ran the program and disconnected - the program continued to run.
it appears that it was set up to do something like that, but they couldn't actually log into your machine
one thing you could do is take your "security" log (start > run > eventvwr > windows logs > security) and export them to a CSV file (text)
then do a search for all instances of the username, you'll probably be able to see when it got created... then it's up to you to find out what was going on in the computer at that time... was some local user browsing weird websites, or installing some game or something?
