Login Failed Can Not Be Accessed From This Computer????

Hi tryed all sorts so sent a report to s/l lab it was working fine befor i went on hoilday and cam back after 5 days and when i try to log in it comes up saying (second life can not be accessed from this computer).
no one has accessed my acount as i live alone no one as access to my passwords or anything.
dont know when l/l will get back to me about this and cant seem to find the reason behind this on any of the blogs ect so could anyone help and tell me what it means and way it has happened if i know the reason it will save me from loseing all my hair in the mean time thanx lilly xxxxxx

Would it happen to be at work or at school? Sounds like somebody closed the firewall on ya.

No its a home account and its doing my head in lol
+ am the account holder cant seem to find a answer anywere...lilly xxx

I have also checked all possablitys that firewalls could be blocking me or progammes that can be shut down that are running in the background have been still the same....
hair slowly coming out in chunk lodes lol....lilly xx