Login - "Running low on Resources" message

Hi, I'm running Vista home Premium 32bit, I have had the same message on several occasions now when trying to log in form Sleep mode. Get message saying system running low on resources, please use a user logged in. However there is no user logged in. The only way I can get out of this is by rebooting.
Suggestions as to cause and a remedy would be most welcome.

Thanks
Andy

I have been experiencing the same problem in both x32 and x64 with all versions of Vista and Windows 7 that have multiple logins. Once it goes to sleep and wakes up, the message appears when trying to login. Some of the site suggest resources of RAM but I have 4GB of RAM in all of my systems. Seems as though Microsoft hasn't fixed this problem for many years and cannot believe that more people haven't complained. If anyone has a fix or a bug number, please post.

Thank you,

SavageTribe