The easiest solution to this problem would be download the latest version of SETISpy, available here.
For users with versions before 3.1.1, here is the solution:
This question gets asked a lot here. Here is a quick guide to correcting the problem, found on the SETISpy Web Site.
Recently, the Update button on the User Statistics screen has stopped working, and the User Name hyperlink has disappeared. What happened?
I have tracked the problem down to the user_info.sah file, which SETI@home uses to store user information. My best guess is that due to recent security breaches, SETI@home management has decided not to include the user email address in the user_info.sah file like they used to. SETI Spy cannot update the user stats without the user email address. SETI Spy 3.0.6 and later provides a workaround, but you have to edit the setispy.ini file using the following steps.
Stop your SETI Spy if it is running.
Download the latest version of SETI Spy (3.0.6 or later) if you have not already done so.
Open the setispy.ini file in your SETI@home folder with a text editor like NotePad.
Add a line "BackupEmailAddr=youraddress@yourISP.com" just below the UserPercentage= line in the [Stats] section. Do not use quotes, and replace youraddress@yourISP.com with the email address you log into SETI@home with. The [Stats] section should now look something like the image below, with the added line shown in red. Don't worry of the lines are not exactly in the same order. Just add the BackupEmailAddr= line below the UserPercentage= line.
GroupName=Broadband Reports Team Starfire
Start SETI Spy.