Helping people with computers... one answer at a time.
If the SYSTEM32 folder opens on log in it's normally the result of a broken start-up entry or a virus. There are steps you can take to correct it.
Why does my System32 folder open when I log in?
As I discussed in a previous article, a lot can happen when you start up or login to Windows. Some of it you want, some of it you don't, and some of it you don't even know about unless you go looking. But every once in a while we come across the strange, unexpected, or bizarre. Several people reported that the system32 folder would open automatically when they logged in. They'd close it and everything seemed fine.
A minor annoyance, or a symptom of a more serious issue?
As it turns out, Microsoft even has a knowledgebase article on the scenario here. It describes how an improper registry setting can cause the problem and one way of dealing with the issue - editing the registry entry directly.
In many cases the solution is actually just a little bit easier. Run msconfig or autoruns (both described in this article) and look for a startup entry that matches that described in the knowledgebase article - that's likely the cause of the problem. Do your best to make sure that it's not something important, certainly save the text somewhere (copy/paste it to a text file or even write it down), delete it and you should be fine.
Of course the next question is how did it get there? Since things that happen at startup time are usually created by setup programs it's certainly possible that a poorly written setup program could have had a problem and left an incomplete or corrupt entry. If you've installed or tried to install anything recently and the problem began then, then that's a likely scenario.
The other scenario is one we've been hearing much about lately: a virus. The viruses that have been making the news are all fairly sophisticated and apparently well written. But of course not all of them are. It's quite possible that a problematic virus either has infected or has tried to infect your machine. Viruses also like to make things happen at start-up. If they have a problem when writing that startup-entry then this type of problem can result.
The advice? You've heard it before:
Get a good anti-virus package
Make sure the virus signatures are up to date
Scan for viruses on a regular basis
Don't open email attachments from people you don't know
Have a good firewall solution in place