NT4 SP6a Proxy 2.0 freezes every hour

I have a PDC running NT4 SP6a and Proxy 2.0 . After deleting the URLCache Folder the server hangs every hour or so. I uninstalled and reinstalled IIS and Proxy. That did not solve the problem. I have recreated the URLCache. This for my company LAN. I need a quick answer or a direction the work in. Thanks!