If it suddenly started happening, I would check with your ISP to see if they are having any problems. I would also run antivirus and anti-trojan (such as Spybot Search & Destroy) just to see if maybe you got something that is interfering in some way. Basically, if it suddenly starts up, then there is some change that happened and you need to figure out what changed.

Invision Support
#Invision on irc.irchighway.net