Trouble with 10g after Installing Grid Control

Question

Main problem: after installing Grid Control and rebooting, I can no longer access my databases.
I have 10g installed on a fairly decent Windows XP machine. It was running okay, but I had two Oracle database instance processes running at 200mb of RAM each (of a total of 1 GB of RAM), so it was a bit bogged down, as is to be expected when running Oracle as a server on Windows.
I then installed Grid Control, which seemed to go okay, and another database as well. But once the install completed, and I gained access to the Grid Control version of the OEM for the first time, that's when things got wacky. Connecting to any OEM instance started taking anywhere from 2-10 minutes, everything was bogged down considerably, etc. I tried shutting everything down and rebooting, but now things are worse. OEM is timing out and not finding servers, listener is timing out, etc. I've tried manipulating a few things in Net Manager (I noticed that my LISTENER section didn't seem to contain any data at all, and my databases weren't listed in there either) with no result.
I've also had trouble with "host credentials" and being able to administer the databases within the OEM, even after implementing a fix I had found to add my user name to a "log on as batch job" local security policy.
Finally, I noticed that after installing Grid Control, when I run "sqlplus", I now see "Oracle91 Enterprise Edition" instead of the "Oracle10g" it used to show (and I never had anything but 10g installed on this machine!).
Here's what happens when I try to access my dBs:
-When I try to launch the OEM connected to any of the 3 databases I created (which were previsouly running), the browser just times out with "page cannot be displayed".
-When I run "emctl start <ANYTHING>" I get file/path not found errors, and a file path with both forward and backward slashes (starting after the "agent" directory):
C:\oracle\product\10.1.0\agent/<...etc.>
-When I try to test a connection to a service in Net Manager, I get this error:
ORA-12557: TNS:protocol adapter not loadable
I had to manually add my listener info and databases info(under Service Naming) in Net Manager, but everything appeared fine in Oracle Directory Manager (unfortunately, that doesn't help much, since this is just a general info tool).
I am nothing near a DBA and my knowledge is limited, so I apologize for not being more consise, but I'd be glad to elaborate if someone could tell me what they need to know.
Thank you,
John

Answer 1

Yes; thank you both. Although I had 1 GB physical and 1.5 GB virtual memory configured, running Grid Control seemed to completely kill all available resources.
I have removed GC and its related database and applications, and I can again conncet to my databases via Database Control. Thank you.
By the way, another issue has arisen, seemingly in the aftermath of installing GC: my OEM Database Control instances now time out after about 60 seconds, logging me out each and every time. I have cookies enabled, but this doesn't seem to be the trouble. Is there a Web setting somewhere that will kick users out of the instance at timed intervals?