Since yesterday afternoon...one of my 5 PC's is now getting the following error on updates...either manual or automatic:

Any ideas on how to correct this ?
Win 7 Pro 32bit (SP 1)
3.00 GB memory
System (BDIS 2011) has run fine.... ie... error free... prior to this error...did update in the last week (3/9 ) to Windows Service Pak 1...but problem started about 24 hrs ago ?
Thanks...