MSN and Internet Game Not Working

After using both extensively last night, I'm now unable to connect to either. MSN gives me an 80048820 error accompanied with an 80048439 one and from searching online it seems to suggest that my date/time might be out of sync. However trying to sync them just leads to another error which isn't described very well.

Using MSN's troubleshooter suggests a Host file error along with some proxy/firewall settings. I haven't changed anything since last night, it just seemed to appear after starting up my laptop this morning.

My MMO just stays at the 'Connection' stage until it times out and closes down.

Any thoughts on how to fix it? System restore maybe?