In my task manager, I have two entries for svchost.exe - one taking up 300MB of memory and the other 75MB.
Is that normal? If not, what should I do? What can the problem be? I don't remember seeing svchost.exe take up this much memory before.
OS: Windows Vista Home Premium SP1
Having two entries for svchost.exe is not a problem. It is not uncommon to see several entries. For a bit of an explaination about the svchost.exe process, see the question What does the svchost.exe process do?.
As for the memory, 300MB does seem like a lot for a single instance. Have a look at the question svchost eating up memory and take a look at the process. If the process is hosting several services 300 MB might be reasonable, but if not the tool mentioned in the question, Process Explorer, can help you to determine which process is causing the problems.
It's normal. svchost is basically the helper process for background Windows and other applications' services, so it can be running multiple tasks at the same time. And two copies of svchost is nothing; sometimes I have as many as 12. If the memory it's consuming is really bugging you, just restart your computer.
Start up in safe mode, open Task manager and take a screenshot of running services. Start up normally, do the same, compare the two and start deleting services. I got rid of a 400 MB svchost.exe instance this very way.
