Sharepoint Web site named "companyweb" was working correctly with no issues on a 2008 R2 server with IIS 7. Once SBS 2008 was installed on another server as part of the domain now clients can connect to this site fine for a while then it stops working. After checking DNS the right server is being reported for this site but when the FQDN is used in browser it pops up credentials but once entered page is blank. Once servers are both rebooted everything works for a while then returns to same results. Any Ideas or good places to start looking for the cause.