Svchost error 0xc000009c

Hi, I recently started having trouble starting up Windows XP. I was away for a week, and when I came back and started up my computer, it came up with an error message at the login screen. It's an svchost.exe error saying that required data was not placed into memory because of an I/O error status of "0xc000009c". Since I've been getting these errors, my computer has been very slow logging in, and I have not had sound or been able to access our wireless network.

I've tried many things, but so far none of them has worked. It just keeps doing the same thing at startup. It seems that the only reliable solution I've seen is to buy a registry cleaner for $30 or so, but I'd rather not spend the money if I don't have to. Has anyone else had this error and knows how to fix it? If it helps, my computer has also been notifying me that there are updates available for Windows XP (including SP3, and some security updates) and Symantec Antivirus, but I haven't been able to because I can't get on the Internet.

Any help would be greatly appreciated!
-Sean