Outlook trying to log multiple attempts to Exchange Server

[EG1979]

I had an issue last year, which has begun to re-occur again.
My outlook 2010 client is connected to the exchange server (2010). However on the exchange server side, there are multiple (hundreds) of Audit Failures with my login credentials of type 4625. There are occurring approximately every 5 seconds. On the client side, I can correspond these audit failures to 100s of Audit Success 4648 connections from my Event Viewer->Security Events, also occurring every 5 seconds. Why is Outlook doing this?
My first suspicion is that I may have some sort of virus on my laptop. I ran several different AV scans, with nothing being returned. Eventually I backup up my data and re-formated my machine. I installed AV software from the get-go (NOD32) and restored my backup data.
Everything was ok until a few days ago when the issue started occurring again. I am part of a large company, and this issue seems to only originate from my machine if we look at the exchange events viewer. I am not sure where to go from here. Has anyone seen this issue before, and if this is related to some sort of virus, how can I go about finding the root cause? Is it possible there is something hiding in my PST that cannot be found with typical AV software?
Also to note, when I close my outlook client, the problem goes away. I am able to access my email via the web interface (webmail). My company has instructed me not to use outlook until the problem is resolved, as it may be related to a blacklisting for spam that recently occurred.
Is my mail client the cause of this? Please help.
My mailbox is also reached its limit. Is it possible for this behavior to be the cause of this?

Regards.


EG1979